$ git clone -n https://src.fedoraproject.org/rpms/mono.git /var/lib/mock/f39-build-1871693-42717/root/chroot_tmpdir/scmroot/mono
Cloning into '/var/lib/mock/f39-build-1871693-42717/root/chroot_tmpdir/scmroot/mono'...
$ git fetch origin 0618c218c5f4b31441225205a98d5d53dc664c62:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mono
 * [new ref]         0618c218c5f4b31441225205a98d5d53dc664c62 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0618c21 Upgrade to Mono 6.12.0.199