$ git clone -n https://src.fedoraproject.org/rpms/plymouth-kcm.git /var/lib/mock/f42-build-side-1-3505164-45989/root/chroot_tmpdir/scmroot/plymouth-kcm
Cloning into '/var/lib/mock/f42-build-side-1-3505164-45989/root/chroot_tmpdir/scmroot/plymouth-kcm'...
$ git fetch origin 9b39eab4481cc2705c1805245c293220e82be627:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/plymouth-kcm
 * [new ref]         9b39eab4481cc2705c1805245c293220e82be627 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9b39eab 6.3.4