Unlike the Finder (with its notorious .DS_Store files) we use no
hidden files, we do not require files scattered around in every
directory, and no helper files will ever silently appear on your
network shares or external hard drives.
Path Finder 4.8 will store its visual per-folder settings in a
centralized SQLite database located in ~/Library/Application
Support/Path Finder/CoreData. Its size is very small - mine
currently weighs just about 150 KB.