I checked and you're right: The endpoint that returns the file list has a hardcoded set of excludes and pays no attention to `.gitattributes`.

I think it's reasonable to respect the linguist overrides here so I'll open a PR to remove entries from the exclude if the repo has a `-linguist-generated` or `-linguist-vendored` gitattribute for that directory [1]. So in your case you can add

  build/** -linguist-generated

to `.gitattributes` and once my PR lands files under `build` should be findable in file-finder.

Thanks for pointing this out! Feel free to DM me on twitter (@cbrasic) if you have more questions.

[1] Recursively matching a directory with gitattributes requires the `/**` syntax unlike .gitignore: https://git-scm.com/docs/gitattributes#:~:text=with%20a%20fe...