The 'languageshtml' result property for action=parse has been deprecated
for some time now, and with the merge of Gerrit change 143299[1] is now
removed entirely. This will be deployed to WMF wikis with 1.24wmf12; see
https://www.mediawiki.org/wiki/MediaWiki_1.24/Roadmap for the schedule.
[1]:
https://gerrit.wikimedia.org/r/#/c/143299/
--
Brad Jorsch (Anomie)
Software Engineer
Wikimedia Foundation