Please add en-in as "Indian English".
For comparison consider that Phabricator (or whatever controls the Wikidata language process) has already logged
British English (en-gb)
Canadian English (en-ca)
Indian English is, of course, more different and spoken by many more people than these other two. I expect that adding en-in is noncontroversial in the context of these other two existing already.
My objective for this is to get Indian English text noted as such in Wikidata language property fields. I asked about this at the Wikidata Project Chat at
and the answer was to request here on Phabricator.