$ git clone -n https://src.fedoraproject.org/rpms/R-magick.git /var/lib/mock/f40-build-1944520-25177/root/chroot_tmpdir/scmroot/R-magick
Cloning into '/var/lib/mock/f40-build-1944520-25177/root/chroot_tmpdir/scmroot/R-magick'...
$ git fetch origin 0cb1211ba1b930a8e0825ffede69836350037919:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/R-magick
 * [new ref]         0cb1211ba1b930a8e0825ffede69836350037919 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 0cb1211 R-maint-sig mass rebuild