$ git clone -n https://src.fedoraproject.org/rpms/R-pkgload.git /var/lib/mock/f42-build-side-1-3522752-46188/root/chroot_tmpdir/scmroot/R-pkgload
Cloning into '/var/lib/mock/f42-build-side-1-3522752-46188/root/chroot_tmpdir/scmroot/R-pkgload'...
$ git fetch origin 7a4beacf4b84848af5a995db9a2867f5fb9e145f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-pkgload
 * [new ref]         7a4beacf4b84848af5a995db9a2867f5fb9e145f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 7a4beac Update to latest version