$ git clone -n https://src.fedoraproject.org/rpms/ghc-th-orphans.git /var/lib/mock/f39-build-1712011-41228/root/chroot_tmpdir/scmroot/ghc-th-orphans
Cloning into '/var/lib/mock/f39-build-1712011-41228/root/chroot_tmpdir/scmroot/ghc-th-orphans'...
$ git fetch origin e337cb73079c49d56bcd2f8758608972a4cdf4a0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-th-orphans
 * [new ref]         e337cb73079c49d56bcd2f8758608972a4cdf4a0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at e337cb7 bump release