$ git clone -n https://src.fedoraproject.org/rpms/gnome-builder.git /var/lib/mock/f41-build-836136-158771/root/chroot_tmpdir/scmroot/gnome-builder
Cloning into '/var/lib/mock/f41-build-836136-158771/root/chroot_tmpdir/scmroot/gnome-builder'...
$ git fetch origin 959d26c84f07b12b48ae03b99878dc2613983850:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-builder
 * [new ref]         959d26c84f07b12b48ae03b99878dc2613983850 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 959d26c Update to 47.beta