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: [[ https://phabricator.wikimedia.org/rSVN59035 | $wgAllowMicroDataAttributes is introduced ]], it requires `$wgHTML5`.
- MW 1.22: [[ https://gerrit.wikimedia.org/r/#/c/63106/ | $wgHTML5 is removed ]]