/usr/local/Frameworks vs /Library/Frameworks

I’ve installed python using brew and I see the framework is symlinked from the Cellar to /usr/local/Frameworks instead of /Library/Frameworks.

This confuses me because all documentation regarding frameworks I’ve found suggest to use one of the four Library folders (user, local, system, network) and, in this case, /Library/Frameworks (that is the local Library) seems the most appropriate one and, indeed, is what the official python installer for MacOS uses.

I understand the usage of the standard unix directory structure for *nix packages, but why also for frameworks whose location is well defined and documented by Apple?

PS: I posted this first in https://github.com/Homebrew/discussions/discussions/138 because I didn’t know of this site. Feel free to close one of the conversations.