$ git clone -n https://src.fedoraproject.org/rpms/gnome-shell-extensions.git /var/lib/mock/f40-build-2240790-53649/root/chroot_tmpdir/scmroot/gnome-shell-extensions
Cloning into '/var/lib/mock/f40-build-2240790-53649/root/chroot_tmpdir/scmroot/gnome-shell-extensions'...
$ git fetch origin 13ad0a285a1122ac94af5d2301433be496c212b0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnome-shell-extensions
 * [new ref]         13ad0a285a1122ac94af5d2301433be496c212b0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 13ad0a2 Update to 46.alpha