How does the GitHub Actions Cache size limit work for Pull Requests?

[lhotari]

How does the GitHub Actions Cache size limit work for Pull Requests?

Is the quota for the cache size limit per-user repository (forked repository, where the pull request branch is contained) or for the repository where the pull request is created?

Because of security reasons, a pull request build cannot update the upstream repository’s GitHub Action cache. When the cache gets updated, I would assume that the cache gets stored in the cache associated with the user’s branch and forked repository and thus consumes the quota of the forked repository instead of the upstream repository quota.

Is this the correct understanding?

It would be great to have an explanation in the cache documentation at https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#usage-limits-and-eviction-policy .

I have also asked this question in GitHub Community forum for GitHub Actions.