$ git clone -n https://src.fedoraproject.org/rpms/R-pingr.git /var/lib/mock/f42-build-side-1-3501696-45976/root/chroot_tmpdir/scmroot/R-pingr
Cloning into '/var/lib/mock/f42-build-side-1-3501696-45976/root/chroot_tmpdir/scmroot/R-pingr'...
$ git fetch origin 3ca409e44bcef3065c15a67cbcb50ea6d66a5587:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pingr
 * [new ref]         3ca409e44bcef3065c15a67cbcb50ea6d66a5587 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3ca409e R-maint-sig mass rebuild