$ git clone -n https://src.fedoraproject.org/rpms/lazarus.git /var/lib/mock/f42-build-3347404-45004/root/chroot_tmpdir/scmroot/lazarus
Cloning into '/var/lib/mock/f42-build-3347404-45004/root/chroot_tmpdir/scmroot/lazarus'...
$ git fetch origin 1a51fcf09d5a2036c44d2db2e921e2296299c763:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/lazarus
 * [new ref]         1a51fcf09d5a2036c44d2db2e921e2296299c763 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1a51fcf Update to v3.8