Clean up internal doc

_↴ Ported from [flutter/genui#456](https://github.com/flutter/genui/issues/456) — originally opened by [sethladd](https://github.com/sethladd) on 2025-10-27._
_Original labels: P2, sla: missed_

---

Teams inside of Google are finding our internal docs, some of which are outdated. Let's clean those up so those teams have an accurate picture.

For example, this one: /mobile/flutter/genui/g3doc/index.md

---

### 1 comment(s) from the original issue

**[sethladd](https://github.com/sethladd)** commented on 2025-10-28:

I put up a CL for this, with a warning that the doc is out of date. We can do more here, so I'll leave the issue open

Find the internal documentation file at /mobile/flutter/genui/g3doc/index.md. Review its content to identify outdated information. Update or remove the outdated sections, ensuring the doc accurately reflects the current state of the project. Check for any similar internal docs that may also need cleanup.

Written by the indexing model from the issue text.