As mentioned on IRC but summarised here for reference: do we want to support PKGCONFBRANCH=latest being set in a user's src.conf on release branches? 0b18e008ccf74ee87d38ca16c9c4d9bb0b174bec deliberately made this an overridable variable, and so it we want to preserve that we probably should have a latest-release file too.

Perhaps also we should be automatically adding the -release suffix to the file name rather than bundling it in PKGCONFBRANCH, since it's not part of the *branch*, it's part of how we pick which implementation is appropriate to get that ports branch for the given src branch. That way you don't break existing configs, whereas this will lead to users with PKGCONFBRANCH set for release branches (whether to quarterly or latest) getting the non-release version of the file, which may not work so well for them.