You can clone with
HTTPS or Subversion.
The Rails repository has an tag named list which doesn't appear to belong (See at https://github.com/rails/rails/tags?after=v0.9.1). I am assuming that this is from someone running git tag list while trying to list the tags - I've done it before myself.
git tag list
I believe this can be fixed by running
git tag -d list
git push origin :refs/tags/list
It doesn't hurt? Not a real issue.