$ git clone -n https://src.fedoraproject.org/rpms/libolm.git /var/lib/mock/f39-build-1490324-34506/root/chroot_tmpdir/scmroot/libolm
Cloning into '/var/lib/mock/f39-build-1490324-34506/root/chroot_tmpdir/scmroot/libolm'...
$ git fetch origin b8191ac840a6676998674f8b8c47e86e2c1bc8da:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libolm
 * [new ref]         b8191ac840a6676998674f8b8c47e86e2c1bc8da -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b8191ac Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild