I discovered that in a Plone install, which had a 1.2.0 five.grok installed, I just had to have a "static" folder in my egg source, and grok would register it appropriately.
When I moved to an environment with a 1.3.0 five.grok installed, this static folder was not registered. I can, of course register it explicitly in the configure.zcml file - which works fine. Checking the source code of five.grok there is indeed a change related to this: the class StaticResourcesGrokker was removed from meta.py between 1.2.0 and 1.3.0 of five.grok.
I'm just trying to understand if there's a new way of having the static folder registered in the "grok way", or should I just revert to using explicit registration in the configure.zcml?