Undocumented GitHub API?

[taranvohra]

I've been playing around with the GH API and found some APIs not documented as part of the official documentation but works as expected. For instance to fetch a repository branches, the docs mentions

GET /repos/{owner}/{repoName}/branches

however this also works GET /repositories/{repoID}/branches

Why is this not documented? Is it not safe to use the latter one? 🤔