$ git clone -n https://src.fedoraproject.org/rpms/qemu-sanity-check.git /var/lib/mock/f39-build-1765388-41501/root/chroot_tmpdir/scmroot/qemu-sanity-check
Cloning into '/var/lib/mock/f39-build-1765388-41501/root/chroot_tmpdir/scmroot/qemu-sanity-check'...
$ git fetch origin ca33a5b7b4924c7bc4454f1b140a4b6d3687a948:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/qemu-sanity-check
 * [new ref]         ca33a5b7b4924c7bc4454f1b140a4b6d3687a948 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ca33a5b Rebase with all latest upstream patches