$ git clone -n https://src.fedoraproject.org/rpms/R-IRanges.git /var/lib/mock/f38-build-724286-99404/root/chroot_tmpdir/scmroot/R-IRanges
Cloning into '/var/lib/mock/f38-build-724286-99404/root/chroot_tmpdir/scmroot/R-IRanges'...
$ git fetch origin 99bd3309c837ca9e296d10378c4201c11b779f9f:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-IRanges
 * [new ref]         99bd3309c837ca9e296d10378c4201c11b779f9f -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 99bd330 R-maint-sig mass rebuild