Codeberg is a non-profit founded specifically to provide a FOSS alternative to GitHub and GitLab for hosting projects. The site is based on Forgejo, which is a community-driven fork of Gitea (both are FOSS, though Gitea is helmed by a for-profit company).
@TheK @alexm42 There's an open PR to implement this. In the meantime, this userscript implements the collapsing functionality.