$ git clone -n https://src.fedoraproject.org/rpms/gnome-radio.git /var/lib/mock/f42-build-side-1-3587071-46927/root/chroot_tmpdir/scmroot/gnome-radio
Cloning into '/var/lib/mock/f42-build-side-1-3587071-46927/root/chroot_tmpdir/scmroot/gnome-radio'...
$ git fetch origin 2a261ccd783f3c5edc8c2ef68dda14a1e270ce79:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-radio
 * [new ref]         2a261ccd783f3c5edc8c2ef68dda14a1e270ce79 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2a261cc gnome-radio 50.1