There are currently 221 branches on the nixpkgs repo. 137 of these are what GitHub calls “stale” (this appears to mean “not touched within the last three months”). Some of them have historical value: certainly release-13.10, maybe staging-21.11, etc. – but others, like llvm15-wip, upvote-convention, and system, appear either obsolete/merged or have no clear purpose in the first place. Many seem like they should have or would have been created on an individual user’s fork and then merged in a PR, but were created on the main repository instead, either by mistake or for the sake of effort.
These branches (particularly make-disk-image/no-nix-store, as it begins with ma) clutter up tab-completion and search, and make interacting with nixpkgs fractionally more annoying than it has to be on an ongoing basis. Is there any interest in trying to gradually clean these up?