$ git clone -n https://src.fedoraproject.org/rpms/plexus-compiler.git /var/lib/mock/f41-build-1185396-22044/root/chroot_tmpdir/scmroot/plexus-compiler
Cloning into '/var/lib/mock/f41-build-1185396-22044/root/chroot_tmpdir/scmroot/plexus-compiler'...
$ git fetch origin 421ffad477a0587ab90d511f36698393737ea4b2:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plexus-compiler
 * [new ref]         421ffad477a0587ab90d511f36698393737ea4b2 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 421ffad Update to upstream version 2.15.0