Add internal Markdown parsing

docs/oss/attribution.md

@@ -12,6 +12,19 @@ License and notices: [BSD 3-Clause](licenses/BSD-3-Clause.txt) | [LICENSE](https
 
 [Source](https://go.googlesource.com/mod/+/d3398d06de5fa5c71083d3d1c26f2cda73508e0f).
 
+## Goldmark
+
+Selected module: `github.com/yuin/goldmark/v2` at `v2.1.6`.
+
+Copyright (c) 2019 Yusuke Inuzuka.
+
+SPDX-License-Identifier: MIT
+
+License and notices: [MIT](licenses/MIT.txt) |
+[LICENSE](https://github.com/yuin/goldmark/blob/a8d4ee5a0bd7d5493fdd1e339b4e75df92f8684c/LICENSE).
+
+[Source](https://github.com/yuin/goldmark/tree/a8d4ee5a0bd7d5493fdd1e339b4e75df92f8684c).
+
 ## Standard Repository Policies
 
 Material: policy documents under `docs/policy/`, the root `AGENTS.md` orientation,