diff --git a/BUILD b/BUILD
index 38137587b..906aed427 100644
--- a/BUILD
+++ b/BUILD
@@ -33,6 +33,11 @@ docs(
             "bundle": "//src/extensions/score_mounts/docs:internals",
             "mount_at": "internals/extensions/mounts",
         },
+        {
+            "bundle": "//src/extensions/score_metamodel/docs:metamodel",
+            "mount_at": "reference/metamodel",
+            "attach_to": "reference/index",
+        },
     ],
     scan_code = [
         "//scripts_bazel:sources",
diff --git a/bzl/bundle_rules.bzl b/bzl/bundle_rules.bzl
index f55cc138a..ace5d796d 100644
--- a/bzl/bundle_rules.bzl
+++ b/bzl/bundle_rules.bzl
@@ -64,6 +64,7 @@ DocsBundleInfo = provider(
         "entries": "Ordered entries, one per source directory, including its final documentation-tree location.",
         "sourcelinks": "Source-code-link JSON files together with their owning repository.",
         "external_runfiles": "Documentation source files from external repositories needed in runfiles.",
+        "data": "Non-source-tree files (e.g. genrule outputs) needed for Sphinx resolution.",
     },
 )
 
@@ -144,7 +145,7 @@ def _bundle_execroot_path(runtime_path):
         return "external/" + runtime_path[3:]
     return runtime_path
 
-def _rebase_bundle_entry(entry, mount_at, attach_to):
+def _rebase_bundle_entry(entry, mount_at, attach_to, data):
     """Place a bundle entry below a requested documentation-tree location.
 
     A bundle's own root has no ``mount_at`` yet. For that root, an omitted
@@ -165,6 +166,7 @@ def _rebase_bundle_entry(entry, mount_at, attach_to):
         entry_doc = entry.entry_doc,
         external = entry.external,
         repository = entry.repository,
+        data = data,
     )
 
 def _entries_visible_through(ctx, child):
@@ -210,6 +212,7 @@ def _docs_bundle_impl(ctx):
     entries = []
     own_source_files = []
     own_external_runfiles = []
+    own_data = depset(direct = ctx.files.data)
 
     if ctx.files.srcs:
         runtime_path = _bundle_runtime_path(ctx)
@@ -225,12 +228,25 @@ def _docs_bundle_impl(ctx):
             entry_doc = ctx.attr.entry_doc,
             external = external,
             repository = ctx.label.workspace_name,
+            data = own_data,
         ))
         own_source_files.extend(ctx.files.srcs)
         # Local sources are read directly from the workspace by ``bazel run``.
         # Only sources from external repositories must be staged in runfiles.
         if external:
             own_external_runfiles.extend(ctx.files.srcs)
+    elif own_data:
+        # Pure data bundle: create an entry so the data files appear in the manifest.
+        entries.append(struct(
+            runtime_path = "",
+            src_root = "",
+            mount_at = "",
+            attach_to = "",
+            entry_doc = ctx.attr.entry_doc,
+            external = False,
+            repository = ctx.label.workspace_name,
+            data = own_data,
+        ))
 
     child_source_files = []
     child_external_runfiles = []
@@ -239,11 +255,13 @@ def _docs_bundle_impl(ctx):
         for source_link in ctx.files.sourcelinks
     ]
     for index, child in enumerate(ctx.attr.bundles):
+        child_data = child[DocsBundleInfo].data
         entries.extend([
             _rebase_bundle_entry(
                 entry,
                 ctx.attr.bundle_mount_ats[index],
                 ctx.attr.bundle_attach_tos[index],
+                child_data,
             )
             for entry in _entries_visible_through(ctx, child)
         ])
@@ -260,12 +278,19 @@ def _docs_bundle_impl(ctx):
         direct = own_external_runfiles,
         transitive = child_external_runfiles,
     )
+    all_data = depset(
+        transitive = [own_data] + [
+            child[DocsBundleInfo].data
+            for child in ctx.attr.bundles
+        ],
+    )
     return [
-        DefaultInfo(files = all_source_files),
+        DefaultInfo(files = depset(transitive = [all_source_files, all_data])),
         DocsBundleInfo(
             entries = entries,
             sourcelinks = sourcelinks,
             external_runfiles = external_runfiles,
+            data = all_data,
         ),
     ]
 
@@ -279,11 +304,12 @@ _docs_bundle = rule(
         "bundles": attr.label_list(providers = [DocsBundleInfo]),
         "bundle_mount_ats": attr.string_list(),
         "bundle_attach_tos": attr.string_list(),
+        "data": attr.label_list(allow_files = True),
     },
     doc = "Internal rule that carries bundle files and their documentation-tree locations.",
 )
 
-def create_bundle(name, bundles, srcs = [], sourcelinks = [], strip_prefix = "", entry_doc = "index", visibility = None, **kwargs):
+def create_bundle(name, bundles, srcs = [], sourcelinks = [], strip_prefix = "", entry_doc = "index", data = [], visibility = None, **kwargs):
     """Create a reusable documentation bundle from files and child declarations."""
     parsed_bundles = [_parse_bundle_declaration(declaration) for declaration in bundles]
     _docs_bundle(
@@ -295,6 +321,7 @@ def create_bundle(name, bundles, srcs = [], sourcelinks = [], strip_prefix = "",
         bundles = [bundle.bundle for bundle in parsed_bundles],
         bundle_mount_ats = [bundle.mount_at for bundle in parsed_bundles],
         bundle_attach_tos = [bundle.attach_to for bundle in parsed_bundles],
+        data = data,
         visibility = visibility,
         **kwargs
     )
@@ -302,7 +329,10 @@ def create_bundle(name, bundles, srcs = [], sourcelinks = [], strip_prefix = "",
 
 def _external_docs_runfiles_impl(ctx):
     """Expose external documentation sources needed under ``bazel run``."""
-    return [DefaultInfo(files = ctx.attr.bundle[DocsBundleInfo].external_runfiles)]
+    bundle = ctx.attr.bundle[DocsBundleInfo]
+    return [DefaultInfo(files = depset(
+        transitive = [bundle.external_runfiles, bundle.data],
+    ))]
 
 _external_docs_runfiles = rule(
     implementation = _external_docs_runfiles_impl,
diff --git a/bzl/mount_rules.bzl b/bzl/mount_rules.bzl
index aa710795d..562de5996 100644
--- a/bzl/mount_rules.bzl
+++ b/bzl/mount_rules.bzl
@@ -18,7 +18,8 @@ load("@score_docs_as_code//:bzl/bundle_rules.bzl", "DocsBundleInfo")
 
 def _mounts_manifest_impl(ctx):
     """Generate the canonical Sphinx mount manifest."""
-    entries = ctx.attr.bundle[DocsBundleInfo].entries
+    bundle_info = ctx.attr.bundle[DocsBundleInfo]
+    entries = bundle_info.entries
 
     json_mounts = []
     for entry in entries:
@@ -29,6 +30,7 @@ def _mounts_manifest_impl(ctx):
             "attach_to": entry.attach_to,
             "entry_doc": entry.entry_doc,
             "external": entry.external,
+            "data": [f.path for f in entry.data.to_list()],
         })
 
     out = ctx.actions.declare_file(ctx.label.name + ".json")
diff --git a/docs.bzl b/docs.bzl
index 0ac56327e..1f4e41a92 100644
--- a/docs.bzl
+++ b/docs.bzl
@@ -61,7 +61,7 @@ load(
     "create_mounts_manifest",
 )
 
-def docs_bundle(name, source_dir = None, entry_doc = "index", bundles = [], scan_code = [], code_targets = [], visibility = None, **kwargs):
+def docs_bundle(name, source_dir = None, data = [], entry_doc = "index", bundles = [], scan_code = [], code_targets = [], visibility = None, **kwargs):
     """A docs bundle, optionally composed of others.
 
     Args:
@@ -69,6 +69,9 @@ def docs_bundle(name, source_dir = None, entry_doc = "index", bundles = [], scan
       source_dir: optional directory holding this bundle's own doc sources. It is
         globbed like `docs()` (same file kinds) and the contents are stored after
         stripping the `source_dir` prefix. Leave it unset for a pure aggregator.
+      data:
+        Additional data dependencies for this target.
+        Useful for generated rst sources.
       entry_doc: bundle-relative docname attached when this bundle is mounted.
         Defaults to `index`.
       bundles: nested bundles to compose, each a dict
@@ -113,6 +116,7 @@ def docs_bundle(name, source_dir = None, entry_doc = "index", bundles = [], scan
         strip_prefix = strip_prefix,
         entry_doc = entry_doc,
         bundles = bundles,
+        data = data,
         visibility = visibility,
         **kwargs
     )
diff --git a/src/extensions/score_metamodel/docs/BUILD b/src/extensions/score_metamodel/docs/BUILD
new file mode 100644
index 000000000..30b89e9a6
--- /dev/null
+++ b/src/extensions/score_metamodel/docs/BUILD
@@ -0,0 +1,42 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+load("//:docs.bzl", "docs_bundle")
+load("@aspect_rules_py//py:defs.bzl", "py_binary")
+load("@docs_as_code_hub_env//:requirements.bzl", "all_requirements")
+
+genrule(
+    name = "generate_metamodel_rst",
+    srcs = [
+        "//src/extensions/score_metamodel:metamodel_yaml",
+    ],
+    outs = ["generated/index.rst", "generated/metamodel_classes.mmd"],
+    cmd = "$(location :generate_metamodel_rst_bin) --rst-output $(location generated/index.rst) --mmd-output $(location generated/metamodel_classes.mmd) $(location //src/extensions/score_metamodel:metamodel_yaml)",
+    tools = [":generate_metamodel_rst_bin"],
+    visibility = ["//visibility:private"],
+)
+
+py_binary(
+    name = "generate_metamodel_rst_bin",
+    srcs = ["generate_metamodel_rst.py"],
+    main = "generate_metamodel_rst.py",
+    deps = all_requirements,
+    visibility = ["//visibility:private"],
+)
+
+docs_bundle(
+    name = "metamodel",
+    data = [":generate_metamodel_rst"],
+    entry_doc = "index",
+    visibility = ["//visibility:public"],
+)
diff --git a/src/extensions/score_metamodel/docs/generate_metamodel_rst.py b/src/extensions/score_metamodel/docs/generate_metamodel_rst.py
new file mode 100644
index 000000000..423cc8947
--- /dev/null
+++ b/src/extensions/score_metamodel/docs/generate_metamodel_rst.py
@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+"""Generate an RST file with a list-table and Mermaid class diagram from metamodel.yaml.
+
+Usage:
+    generate_metamodel_rst.py --rst-output FILE --mmd-output FILE [METAMODEL_YAML]
+"""
+
+from __future__ import annotations
+
+import argparse
+import sys
+from pathlib import Path
+
+import ruamel.yaml
+
+
+def _parse_yaml(path: Path) -> dict:
+    yaml = ruamel.yaml.YAML()
+    yaml.preserve_quotes = True
+    with Path(path).open(encoding="utf-8") as fh:
+        return yaml.load(fh)  # type: ignore[no-any-return]
+
+
+def _build_table(types: dict) -> list[str]:
+    lines: list[str] = []
+    lines.append(".. list-table:: Need Types")
+    lines.append("   :header-rows: 1")
+    lines.append("")
+    lines.append("   * - Type")
+    lines.append("     - Title")
+    lines.append("     - Mandatory Options")
+    lines.append("     - Links")
+    for name, ty in sorted(types.items()):
+        title = ty.get("title", name)
+        mandatory = (
+            ", ".join(sorted(ty.get("mandatory_options", {}).keys())) or "\u2014"
+        )
+        optional_links = ", ".join(sorted(ty.get("optional_links", {}).keys()))
+        mandatory_links = ", ".join(sorted(ty.get("mandatory_links", {}).keys()))
+        if mandatory_links:
+            links = f"{optional_links} | mandatory: {mandatory_links}"
+        else:
+            links = optional_links or "\u2014"
+        lines.append("   * - " + name)
+        lines.append("     - " + title)
+        lines.append("     - " + mandatory)
+        lines.append("     - " + links)
+    return lines
+
+
+def _build_mermaid(types: dict) -> list[str]:
+    lines: list[str] = []
+    seen: set[tuple[str, str, str]] = set()
+    for name, ty in sorted(types.items()):
+        for link_name, targets in sorted(
+            list(ty.get("mandatory_links", {}).items())
+            + list(ty.get("optional_links", {}).items())
+        ):
+            target_types = targets.split(", ") if targets != "ANY" else []
+            for target in target_types:
+                target = target.strip()
+                if target and target in types:
+                    key = (name, target, link_name)
+                    if key not in seen:
+                        seen.add(key)
+                        lines.append(f"{name} --> {target} : {link_name}")
+    return lines
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser(description="Generate RST from metamodel.yaml")
+    parser.add_argument("--rst-output", type=Path, required=True)
+    parser.add_argument("--mmd-output", type=Path, required=True)
+    parser.add_argument("metamodel", nargs="?", default=None)
+    args = parser.parse_args()
+
+    meta_path = (
+        Path(args.metamodel)
+        if args.metamodel
+        else Path(__file__).parent / "metamodel.yaml"
+    )
+    if not meta_path.is_file():
+        print(f"Error: metamodel.yaml not found at {meta_path}", file=sys.stderr)
+        return 1
+
+    try:
+        data = _parse_yaml(meta_path)
+    except Exception as exc:
+        print(f"Error parsing YAML: {exc}", file=sys.stderr)
+        return 1
+
+    types = data.get("needs_types", {})
+    if not types:
+        print(
+            "Error: 'needs_types' section not found in metamodel.yaml", file=sys.stderr
+        )
+        return 1
+
+    table = _build_table(types)
+    mermaid_lines = ["classDiagram"] + _build_mermaid(types)
+    args.mmd_output.write_text("\n".join(mermaid_lines) + "\n", encoding="utf-8")
+    output = "\n".join(
+        [
+            "..",
+            "   # (generated \u2014 do not edit)",
+            "   # SPDX-License-Identifier: Apache-2.0",
+            "",
+            ".. _metamodel-types-visualization:",
+            "",
+            "Metamodel Types Visualization",
+            "==============================",
+            "",
+            f".. mermaid:: {args.mmd_output.name}",
+            "",
+            "Need Types",
+            "----------",
+            "",
+        ]
+        + table
+        + [""]
+    )
+
+    args.rst_output.write_text(output, encoding="utf-8")
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())
diff --git a/src/extensions/score_mounts/__init__.py b/src/extensions/score_mounts/__init__.py
index 0aa79255b..9b6124fee 100644
--- a/src/extensions/score_mounts/__init__.py
+++ b/src/extensions/score_mounts/__init__.py
@@ -32,6 +32,8 @@
 from sphinx.util import logging
 
 from src.extensions.score_mounts._resolver import (
+    MountsManifest,
+    MountSpec,
     load_mounts_manifest,
     resolve_walk_dir,
 )
@@ -63,6 +65,54 @@ def _read_manifest(config: Config):
     return load_mounts_manifest(manifest_path)
 
 
+def _resolve_data_mounts(
+    manifest: MountsManifest,
+    ws_root: Path | None,
+    runfiles_dir: Path | None,
+) -> dict[str, MountSpec]:
+    """Resolve data file mounts from the manifest.
+
+    Data paths are execroot-relative (e.g. bazel-out/.../bin/src/.../index.rst).
+    Returns resolved mount dicts keyed by directory.
+    """
+    data_mounts: dict[str, MountSpec] = {}
+    for spec in manifest.mounts:
+        for data_file in spec.data:
+            if ws_root is not None and runfiles_dir is not None:
+                runfiles_str = str(runfiles_dir)
+                if "/bazel-out/" in runfiles_str:
+                    # Execroot = runfiles path before the first /bazel-out/ occurrence
+                    # e.g. runfiles=execroot/_main/bazel-out/... => execroot=execroot/_main
+                    walk_file = Path(runfiles_str.split("/bazel-out/")[0]) / data_file
+                else:
+                    walk_file = (
+                        ws_root
+                        / "bazel-bin"
+                        / data_file.removeprefix("bazel-out/k8-fastbuild/bin/")
+                    )
+            else:
+                walk_file = Path.cwd() / data_file
+            if not walk_file.is_file():
+                raise ValueError(
+                    "score_mounts: resolved data file does not exist: "
+                    f"{walk_file} (mount_at={spec.mount_at})"
+                )
+            walk_dir = walk_file.parent
+            if str(walk_dir) not in data_mounts:
+                data_mounts[str(walk_dir)] = spec
+    return data_mounts
+
+
+def _make_mount_entry(walk_dir: Path, spec: MountSpec) -> dict[str, object]:
+    """Build a mount entry dict from a resolved directory and spec."""
+    return {
+        "dir": str(walk_dir),
+        "mount_at": spec.mount_at,
+        "attach_to": spec.attach_to,
+        "entry_doc": spec.entry_doc,
+    }
+
+
 def _on_config_inited(app: Sphinx, config: Config) -> None:
     """Translate the Bazel manifest into ``sphinx_mounts`` runtime config.
 
@@ -75,6 +125,9 @@ def _on_config_inited(app: Sphinx, config: Config) -> None:
     if manifest is None or not manifest.mounts:
         return
 
+    ws_root = find_ws_root()
+    runfiles_dir = get_runfiles_dir() if ws_root is not None else None
+
     # In every context sphinx_mounts walks the bundle's original files (no copy is
     # made); only where those files are staged differs:
     #   * external bundle: use its runfiles-relative location under ``bazel run``
@@ -85,28 +138,32 @@ def _on_config_inited(app: Sphinx, config: Config) -> None:
     #     as inputs at their exec-root-relative path. The manifest lives under
     #     bazel-out/ and is NOT colocated with them, so src_root is resolved
     #     against the exec root (the sphinx action's cwd), not the manifest.
-    ws_root = find_ws_root()
-    runfiles_dir = get_runfiles_dir() if ws_root is not None else None
 
+    # Pure-data bundles have empty src_root; skip directory walk.
     runtime_mounts: list[dict[str, object]] = []
     for spec in manifest.mounts:
+        if not spec.src_root:
+            continue
         walk_dir = resolve_walk_dir(manifest, spec, ws_root, runfiles_dir)
         if not walk_dir.is_dir():
             raise ValueError(
                 "score_mounts: resolved mount dir does not exist: "
                 f"{walk_dir} (mount_at={spec.mount_at})"
             )
-
-        runtime_mounts.append(
-            {
-                "dir": str(walk_dir),
-                "mount_at": spec.mount_at,
-                "attach_to": spec.attach_to,
-                "entry_doc": spec.entry_doc,
-            }
-        )
+        runtime_mounts.append(_make_mount_entry(walk_dir, spec))
 
     config.mounts = runtime_mounts
+
+    # Resolve data (e.g. genrule outputs in bazel-out).
+    # Data paths are execroot-relative (e.g. bazel-out/.../bin/src/.../index.rst).
+    # During bazel run: compute execroot from RUNFILES_DIR; during sandboxed build:
+    # cwd IS the execroot.
+    # Only the parent directories of resolved files are added to mounts.
+    data_mounts = _resolve_data_mounts(manifest, ws_root, runfiles_dir)
+    for walk_dir_str, spec in data_mounts.items():
+        config.mounts.append(_make_mount_entry(Path(walk_dir_str), spec))
+    logger.info("score_mounts: added %d data mount(s)", len(data_mounts))
+
     # Prevent sphinx_mounts._on_load_toml from overwriting our config with a
     # possibly-stale docs/ubproject.toml entry.
     config.mounts_from_toml = None
diff --git a/src/extensions/score_mounts/_resolver.py b/src/extensions/score_mounts/_resolver.py
index a26713992..96ecdfa3d 100644
--- a/src/extensions/score_mounts/_resolver.py
+++ b/src/extensions/score_mounts/_resolver.py
@@ -22,7 +22,7 @@
 
 import json
 import os
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from pathlib import Path
 from typing import cast
 
@@ -35,6 +35,7 @@ class MountSpec:
     attach_to: str | None = None
     entry_doc: str = "index"
     external: bool = False
+    data: list[str] = field(default_factory=list)
 
 
 @dataclass(frozen=True)
@@ -68,6 +69,11 @@ def load_mounts_manifest(manifest_path: str | Path) -> MountsManifest:
             raise ValueError(
                 f"mounts manifest entry missing 'src_root'/'mount_at': {entry!r}"
             )
+        raw_data = entry.get("data", [])
+        if not isinstance(raw_data, list):
+            raise ValueError(
+                f"mounts manifest entry field 'data' must be a list: {raw_data!r}"
+            )
         mounts.append(
             MountSpec(
                 src_root=str(entry["src_root"]),
@@ -78,11 +84,10 @@ def load_mounts_manifest(manifest_path: str | Path) -> MountsManifest:
                 if entry.get("entry_doc")
                 else "index",
                 external=bool(entry.get("external", False)),
+                data=[str(f) for f in cast("list[object]", raw_data)],
             )
         )
-    return MountsManifest(
-        mounts=mounts,
-    )
+    return MountsManifest(mounts=mounts)
 
 
 def resolve_walk_dir(
diff --git a/src/extensions/score_mounts/tests/test_data_mounts.py b/src/extensions/score_mounts/tests/test_data_mounts.py
new file mode 100644
index 000000000..93dc2c4d6
--- /dev/null
+++ b/src/extensions/score_mounts/tests/test_data_mounts.py
@@ -0,0 +1,59 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+"""Tests for ``_resolve_data_mounts`` in the ``score_mounts`` extension."""
+
+from pathlib import Path
+
+import pytest
+
+from src.extensions.score_mounts import _resolve_data_mounts
+from src.extensions.score_mounts._resolver import MountsManifest, MountSpec
+
+
+def test_missing_data_file_raises(tmp_path: Path) -> None:
+    """A manifest with an unavailable data file must fail fast."""
+    manifest = MountsManifest(
+        mounts=[
+            MountSpec(
+                src_root="",
+                runtime_path="",
+                mount_at="missing",
+                data=["bazel-out/k8-fastbuild/bin/nonexistent.rst"],
+            )
+        ]
+    )
+
+    with pytest.raises(ValueError, match="resolved data file does not exist"):
+        _resolve_data_mounts(manifest, tmp_path, tmp_path)
+
+
+def test_existing_data_file_resolved(tmp_path: Path) -> None:
+    """An existing data file resolves to its parent directory."""
+    data_file = tmp_path / "bazel-bin" / "file.rst"
+    data_file.parent.mkdir(parents=True)
+    data_file.write_text("..", encoding="utf-8")
+
+    manifest = MountsManifest(
+        mounts=[
+            MountSpec(
+                src_root="",
+                runtime_path="",
+                mount_at="exists",
+                data=["bazel-out/k8-fastbuild/bin/file.rst"],
+            )
+        ]
+    )
+
+    mounts = _resolve_data_mounts(manifest, tmp_path, tmp_path / "runfiles")
+
+    assert str(tmp_path / "bazel-bin") in mounts
diff --git a/src/extensions/score_sphinx_bundle/__init__.py b/src/extensions/score_sphinx_bundle/__init__.py
index b0d84da5a..975f8bfe8 100644
--- a/src/extensions/score_sphinx_bundle/__init__.py
+++ b/src/extensions/score_sphinx_bundle/__init__.py
@@ -50,6 +50,7 @@ def setup(app: Sphinx) -> dict[str, object]:
 
     # Same as current VS Code extension
     config_setdefault(app.config, "mermaid_version", "11.6.0")
+    config_setdefault(app.config, "mermaid_d3_zoom", True)
 
     # The following entries are not required when building the documentation via
     # 'bazel build //:docs', as that command runs in a sandboxed environment.
diff --git a/src/tests/docs_bzl/scenarios/data_files_runfiles/BUILD b/src/tests/docs_bzl/scenarios/data_files_runfiles/BUILD
new file mode 100644
index 000000000..2c370adc2
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/data_files_runfiles/BUILD
@@ -0,0 +1,46 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+# This fixture exercises the public docs() macro with a data bundle whose
+# only content is a genrule output living in ``bazel-out/.../bin/``.  That
+# output must reach the runfiles of ``:docs`` (via _external_docs_runfiles)
+# and be resolved by ``score_mounts`` at ``bazel run`` time.  See PR #686.
+
+load("//:docs.bzl", "docs", "docs_bundle")
+
+# Emit into a ``generated/`` subdirectory (as the real metamodel bundle does)
+# so the resolved mount directory contains only the genrule output and not the
+# sibling ``docs.runfiles/`` tree.
+genrule(
+    name = "generated_page",
+    srcs = [],
+    outs = ["generated/index.rst"],
+    cmd = """echo 'Generated Data Page
+===================' > $@""",
+)
+
+# Pure-data bundle: the genrule output lives in ``bazel-out/``, not the tree.
+docs_bundle(
+    name = "data_bundle",
+    data = [":generated_page"],
+    entry_doc = "index",
+)
+
+docs(
+    source_dir = "docs",
+    bundles = [{
+        "bundle": ":data_bundle",
+        "mount_at": "data_test",
+        "attach_to": "index",
+    }],
+)
diff --git a/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/conf.py b/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/conf.py
new file mode 100644
index 000000000..3175b997d
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/conf.py
@@ -0,0 +1,16 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+project = "Data Files Runfiles Test"
+project_url = "https://github.com/eclipse-score/docs-as-code"
+extensions = ["score_sphinx_bundle"]
diff --git a/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/index.rst b/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/index.rst
new file mode 100644
index 000000000..fbeefb8f2
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/data_files_runfiles/docs/index.rst
@@ -0,0 +1,20 @@
+..
+   # *******************************************************************************
+   # Copyright (c) 2026 Contributors to the Eclipse Foundation
+   #
+   # See the NOTICE file(s) distributed with this work for additional
+   # information regarding copyright ownership.
+   #
+   # This program and the accompanying materials are made available under the
+   # terms of the Apache License Version 2.0 which is available at
+   # https://www.apache.org/licenses/LICENSE-2.0
+   #
+   # SPDX-License-Identifier: Apache-2.0
+   # *******************************************************************************
+
+Data Files Runfiles Test
+========================
+
+This scenario verifies that ``data`` files (genrule outputs) from a
+``docs_bundle`` reach the runfiles of ``:docs`` and are resolved by the
+Sphinx preview at ``bazel run`` time.
diff --git a/src/tests/docs_bzl/scenarios/nested_bundles/BUILD b/src/tests/docs_bzl/scenarios/nested_bundles/BUILD
index 57a3a30e0..5aab2b04c 100644
--- a/src/tests/docs_bzl/scenarios/nested_bundles/BUILD
+++ b/src/tests/docs_bzl/scenarios/nested_bundles/BUILD
@@ -38,6 +38,13 @@ filegroup(
     srcs = [":filegroup_sources"],
 )
 
+# Simulated generated doc output consumed via the `data` attribute.
+filegroup(
+    name = "generated_doc_output",
+    srcs = ["generated/generated_output.txt"],
+    visibility = ["//visibility:private"],
+)
+
 py_binary(
     name = "example_binary",
     srcs = ["child/example.py"],
@@ -64,6 +71,7 @@ docs_bundle(
         "bundle": ":child",
         "mount_at": "child",
     }],
+    data = [":generated_doc_output"],
 )
 
 # An aggregator deliberately has no source_dir. It only propagates its child
diff --git a/src/tests/docs_bzl/scenarios/nested_bundles/generated/generated_output.txt b/src/tests/docs_bzl/scenarios/nested_bundles/generated/generated_output.txt
new file mode 100644
index 000000000..e97f41e26
--- /dev/null
+++ b/src/tests/docs_bzl/scenarios/nested_bundles/generated/generated_output.txt
@@ -0,0 +1 @@
+Generated documentation output for testing data field propagation.
diff --git a/src/tests/docs_bzl/test_data_files_runfiles.py b/src/tests/docs_bzl/test_data_files_runfiles.py
new file mode 100644
index 000000000..872a0cdeb
--- /dev/null
+++ b/src/tests/docs_bzl/test_data_files_runfiles.py
@@ -0,0 +1,31 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+
+"""Verify that genrule-generated RST files are reachable at ``bazel run`` time.
+
+The ``data`` attribute of ``docs_bundle`` carries genrule outputs that live
+in ``bazel-out/.../bin/``.  The fix in ``_external_docs_runfiles_impl`` stages
+them into the runfiles of ``:docs``; ``score_mounts`` then resolves the
+execroot-relative paths against ``<ws_root>/bazel-bin`` and mounts them.  This
+end-to-end test fails if either half of that chain regresses."""
+
+from src.tests.docs_bzl.helpers import run_scenario
+
+
+def test_data_files_reachable_at_runtime():
+    """Genrule output in a docs_bundle data dep must be resolved by Sphinx."""
+    result = run_scenario("run", "data_files_runfiles", ":docs")
+
+    generated_html = result.build_dir / "data_test" / "index.html"
+
+    assert "Generated Data Page" in generated_html.read_text(encoding="utf-8")
diff --git a/src/tests/docs_bzl/test_nested_bundles.py b/src/tests/docs_bzl/test_nested_bundles.py
index 98390c1a0..0bf1861dc 100644
--- a/src/tests/docs_bzl/test_nested_bundles.py
+++ b/src/tests/docs_bzl/test_nested_bundles.py
@@ -44,6 +44,13 @@ def test_nested_bundles_render_and_preserve_metadata():
         "index",
         "landing",
     ]
+    # Verify that the parent bundle's data (generated doc output) appears in the manifest.
+    parent_mount = next(
+        m for m in manifest["mounts"] if m["mount_at"] == "concepts/example_bundle"
+    )
+    assert parent_mount["data"] == [
+        "src/tests/docs_bzl/scenarios/nested_bundles/generated/generated_output.txt",
+    ]
 
     sourcelinks = json.loads(
         built_output("scenarios/nested_bundles", "sourcelinks_json.json").read_text(