$ git clone -n https://src.fedoraproject.org/rpms/libisofs.git /var/lib/mock/f41-build-817520-14304/root/chroot_tmpdir/scmroot/libisofs
Cloning into '/var/lib/mock/f41-build-817520-14304/root/chroot_tmpdir/scmroot/libisofs'...
$ git fetch origin 55f291b27df9af49c60bcd615fce6dfb1cb27be9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libisofs
 * [new ref]         55f291b27df9af49c60bcd615fce6dfb1cb27be9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 55f291b Eliminate use of obsolete %patchN syntax (#2283636)