Tripette : locut. Little tripod.
It is not worth tripette (or it's tripette): it's worth nothing.
Really nothing.
The expression "not worth tripette": Not worth anything, having absolutely no interest.
Tripette designates a small tripe, this animal gut that is often prepared in the fashion of Caen when you have a packet or in packets when you have it in Provence.
Le Dictionary of Trévoux points out that in the XNUMXth century, the verb tripping meant "to trample under foot," and, by extension, to despise. And as we grant little value to what we despise, it is possible that it is from this verb that the noun tripette was used to designate things without any value, meaning which has remained until our days. in this expression.
Unless, quite simply, too little tripe was considered useless to put in the pot and therefore worthless.