$ git clone -n https://src.fedoraproject.org/rpms/libbs2b.git /var/lib/mock/f45-build-15905-480/root/chroot_tmpdir/scmroot/libbs2b
Cloning into '/var/lib/mock/f45-build-15905-480/root/chroot_tmpdir/scmroot/libbs2b'...
$ git fetch origin 71bf104f3e3b110cf63fd0bc6cb3e1c645db35ff:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libbs2b
 * [new ref]         71bf104f3e3b110cf63fd0bc6cb3e1c645db35ff -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 71bf104 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild