Git Mirrors for GDB's old CVS repository
GDB used CVS as its main CSV up until October 2013, when it moved to git (current git repo).
While the official sources were in CVS, it was possible to use a git mirror for development. Because references to hashes in that repro ended up in GDB's bugzilla and in mailing list discussions, the mirror is kept available for archaeology convenience. (The current git repository shares no ancestry with the old git mirror.)
Here is a list of possible git cvs mirrors that you can choose.
Sourceware's gdb.git: this is the "official" CVS/git mirror, directly for sourceware.org.