$ git clone -n https://src.fedoraproject.org/rpms/rubygem-gtk2.git /var/lib/mock/f40-build-773213-126852/root/chroot_tmpdir/scmroot/rubygem-gtk2
Cloning into '/var/lib/mock/f40-build-773213-126852/root/chroot_tmpdir/scmroot/rubygem-gtk2'...
$ git reset --hard b738e740f90d1bfcba3b6a5b8238d8751d4afe83
HEAD is now at b738e74 fix release