$ git clone -n https://src.fedoraproject.org/rpms/R-processx.git /var/lib/mock/f39-build-2327749-58863/root/chroot_tmpdir/scmroot/R-processx
Cloning into '/var/lib/mock/f39-build-2327749-58863/root/chroot_tmpdir/scmroot/R-processx'...
$ git fetch origin 979fc4c40ebacbe444356642e9586de859f9c74f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-processx
 * [new ref]         979fc4c40ebacbe444356642e9586de859f9c74f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 979fc4c Update to 3.8.2