Strictly speaking, that change means that users can write their own getURL methods (right?), but this implementation still seems to strike a good balance between precision and complexity.

People can write their own getURL predicate, yes. See https://codeql.github.com/docs/writing-codeql-queries/providing-locations-in-codeql-queries/#providing-urls.

Strictly speaking, that change means that users can write their own getURL methods (right?), but this implementation still seems to strike a good balance between precision and complexity.

Yes, and that was always the case, now they just don't get a warning when they do it.

The getURL predicate is special at the language level.
So sometimes it's the right name to use, even if the name doesn't follow our style-guide.

I got some FPs due to that in another PR, so that's why I'm doing this PR.