$ git clone -n https://src.fedoraproject.org/rpms/mg.git /var/lib/mock/f40-build-793087-138784/root/chroot_tmpdir/scmroot/mg
Cloning into '/var/lib/mock/f40-build-793087-138784/root/chroot_tmpdir/scmroot/mg'...
$ git fetch origin b4ef97c05ce2a32cbedcd77b42320877389e2fea:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mg
 * [new ref]         b4ef97c05ce2a32cbedcd77b42320877389e2fea -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b4ef97c Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild