Quite right, except one couldn't use it on just any bike with mudguards, as the hole in the rear brake bridge must be drilled in the vertical rather than the horizonal plane, so that the same vertical bolt can secure both the brake and the mudguard. Seen mostly on French touring bikes and tandems I imagine. I have such a brake on a 60's LeJeune tandem.
Big Spring, Texas, USA
> From: M-gineering <firstname.lastname@example.org>
\r?\n> Subject: Re: [CR] MAFAC 'Racer' variation info sought
\r?\n> Cc: "classicrendezvous" <email@example.com>
\r?\n> Date: Wednesday, December 23, 2009, 8:38 AM
\r?\n> Jay Dubiel wrote:
\r?\n> > I recently acquired a set of Mafac 'Racer' brakes in a
\r?\n> lot with this unusual top mount for the rear brake bridge.
\r?\n> See link to photo: