$ git clone -n https://src.fedoraproject.org/rpms/plasma-thunderbolt.git /var/lib/mock/f42-build-3427241-45202/root/chroot_tmpdir/scmroot/plasma-thunderbolt
Cloning into '/var/lib/mock/f42-build-3427241-45202/root/chroot_tmpdir/scmroot/plasma-thunderbolt'...
$ git fetch origin c9ffc4ce6748a60fb5e7516afb9aa131e9f81060:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plasma-thunderbolt
 * [new ref]         c9ffc4ce6748a60fb5e7516afb9aa131e9f81060 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c9ffc4c 6.3.3