Change the copyright warning for Mediawikiwiki's Help: namespace to CC0. This is currently communicated using an editnotice for namespace 12 but it should be done similar to the Data: namespace on Commons.
If a developer feels like this isn't an uncontroversial request let me know and I'll post a notice to https://www.mediawiki.org/wiki/Project:Village_Pump. Personally I don't see any potential for controversy with this one, but I know how you want to be extra careful sometimes so no hard feelings either way.
Related discussions: