$ git clone -n https://src.fedoraproject.org/rpms/rpm-ostree.git /var/lib/mock/f39-build-1527426-36147/root/chroot_tmpdir/scmroot/rpm-ostree
Cloning into '/var/lib/mock/f39-build-1527426-36147/root/chroot_tmpdir/scmroot/rpm-ostree'...
$ git fetch origin 9f6bff7bc8204f116f860b136614f7a7a55e8162:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rpm-ostree
 * [new ref]         9f6bff7bc8204f116f860b136614f7a7a55e8162 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9f6bff7 Merge branch 'main' into f39