If your externals as single files are installed into a directory "el"
and if not this directory, but the its parent is in Pd's search path
then the object can be used as [el/adsr~] etc. This solution is
standard on Pd-extended, where every collection of abstractions or
externals is installed as a subdirectory of "extra". "extra"
automatically is part of the search path.

That's very cool, thanks. Does this work for core Pd too or are we back to name clashes in that world?

best,

Eric