Modern cars do not, as a rule, use dot 5. It can’t be used, for instance, in anything with ABS because silicon brake fluid absorbs air, and air is what you want to try to keep out of the ABS module.
I hear some of the antique/show car guys run it in their systems, but most of the cars you’d see on a daily basis with vented caps aren’t gonna be running dot 5… At least, not from the factory.