$ git clone -n https://src.fedoraproject.org/rpms/R-IRkernel.git /var/lib/mock/f40-build-2285289-55675/root/chroot_tmpdir/scmroot/R-IRkernel
Cloning into '/var/lib/mock/f40-build-2285289-55675/root/chroot_tmpdir/scmroot/R-IRkernel'...
$ git fetch origin 4b1b96d892b51637fa967209b09e3b9c34eb9a10:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-IRkernel
 * [new ref]         4b1b96d892b51637fa967209b09e3b9c34eb9a10 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 4b1b96d Rebuilt for https://fedoraproject.org/wiki/Fedora_40_Mass_Rebuild