What DaveSSS said makes sense, but that tool does look very much like Mavic's BB chamfering tool.
the 80's/90's Mavic sealed cartridge BBs do not use the bike's BB threading to anchor itself to the frame. It does it with just pressure from 45 degree faced lockrings on both ends of the BB that will seat on to the chamfered faced BB provided by the Mavic tool. A nice idea that would have eliminated all need for trying to figure out what threading your BB is when it comes time to change your BB, but I suspect Mavic wasn't too generous with sharing the patent and technology for this with other companies and it "Betamaxed" itself out of existence, plus other better(?) BB designs came to be afterwards ......although,.......don't Phil Wood BBs kinda work the same way??

Chombi
84 Peugeot PSV
85(?) Vitus Plus Carbone 7