Mike Epstein clarified a policy for the WordPress.org plugin repo this morning, based on some recent issues that cropped up (likely the Elegant Themes / LeadPages thing yesterday). Basically, GPL-compatible unchanged copies are not allowed as part of an “above and beyond” policy:
While the GPL and it’s compatible licenses allow for forking, we have an ‘above and beyond’ rule for hosting here, that means your plugin must be a substantial change of the original. We do not allow direct copies of other plugins to be re-listed under somebody else’s name, we allow changed forks.
What does that mean? It’s very simple. You have to add new features, remove features, modernize, fix, clean up, or otherwise make a change to the plugin that differentiates it from the original. In rare cases, a simple clean-up will be accepted, but normally we try to get a hold of the original authors and have the fixes folded in to the original plugin. If you have a fork, we require you to retain all credit and/or copyright information.
This makes good and perfect sense, as the plugin repo is so visible to Google and anyone managing a WordPress site that it's probably a good policy to have in place. But I didn't really know the official stance today, and now we do.