$ git clone -n https://src.fedoraproject.org/rpms/tcllib.git /var/lib/mock/f45-build-36848-708/root/chroot_tmpdir/scmroot/tcllib
Cloning into '/var/lib/mock/f45-build-36848-708/root/chroot_tmpdir/scmroot/tcllib'...
$ git fetch origin b4e26cf7a32445fa64e1083dc7abe0b812fed38c:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/tcllib
 * [new ref]         b4e26cf7a32445fa64e1083dc7abe0b812fed38c -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4e26cf Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild