It worked fine in extended as long as I listed the directory
in my search path in preferences.

To confirm: That should still be the case. If the path is added to the search paths, it should still work.

I believe the settings files for extended and 0.48 should be different. Did you open the new Pd vanilla and re-add the paths?

One thing to know, those paths are not search recursively, so if you have the following layout, you'll need to add the subdirectories as well:

~/pd-patches
    libA/abstractionA.pd
    libB/abastractionB.pd
    abstractionC.pd

ie. Adding just the main folder will give you abstractionC but not abstractionA or abstractionB.

p.s. I'm not sure if it's bad form for some reason to keep Pd files in my
home directory. If so, I'm open to more information on how to better align
my work flow with the program design.

There's no real "good" or "bad" form. I still use the old "pd-externals" folder myself and added it to my search path directly.

That being said (written?), I did add the Pd "Documents path" helper which creates a canonical place for organizing things. You don't have to use it and you can disable it if you want in the Paths preferences. This feature was added mainly in response to teaching Pd and helping students with organization ala Processing's sketch folder. It's essentially a suggestion, not the "right way".

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Dan Wilcox