$ git clone -n https://src.fedoraproject.org/rpms/janino.git /var/lib/mock/f40-build-2095692-50390/root/chroot_tmpdir/scmroot/janino
Cloning into '/var/lib/mock/f40-build-2095692-50390/root/chroot_tmpdir/scmroot/janino'...
$ git fetch origin c2aa68504e47ca16ad448702ffef4bb4ee1324e5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/janino
 * [new ref]         c2aa68504e47ca16ad448702ffef4bb4ee1324e5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c2aa685 Update to 3.1.10 (#2219584)