The setting $wgAllowMicroDataAttributes could be removed and the microdata attributes could always be allowed.
There doesn't seem to be an evident case use where a wiki could benefit of filtering these attributes, and we now are in HTML 5, so it would simplify MediaWiki configuration.
In the same time, we'll remove $wgAllowRdfaAttributes and so always allow full semantic attributes.
- MW 1.16: $wgAllowMicroDataAttributes is introduced, it requires $wgHTML5.
- MW 1.22: $wgHTML5 is removed