$ git clone -n https://src.fedoraproject.org/rpms/R-glue.git /var/lib/mock/f40-build-1944451-25177/root/chroot_tmpdir/scmroot/R-glue
Cloning into '/var/lib/mock/f40-build-1944451-25177/root/chroot_tmpdir/scmroot/R-glue'...
$ git fetch origin c02473233d3dc3e9a0a8c22c1a0a3969632d6690:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-glue
 * [new ref]         c02473233d3dc3e9a0a8c22c1a0a3969632d6690 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c024732 R-maint-sig mass rebuild