@FOSDEM we concluded that GUIX_PACKAGE_PATH does not necessarily work that wel. I added to my guix-notes the following:
+Note that, even though GUIX_PACKAGE_PATH can be a feasible way of +adding and maintaining packages, it has two largish downsides: (1) it +is removed from the main package tree and therefore not easily shared +and integrated and (2) to remain compatible you need to juggle two git +trees which may go out of synch.
