Hi Lars,

> On 14 Nov 2019, at 07:55, Lars Ingebrigtsen <larsi@gnus.org> wrote:
> 
> I applied the patch anyway, because it provides a way to make the
> backends say whether they support it or not, which seems generally
> useful.

Please install attached patch. Totally missed that default vc functions
are called with `backend` argument.

Thanks.