Note: We are putting this on hold for a little while to work on a communications plan.
With input from the Stewards themselves, the Trust and Safety team has decided that, for security reasons, the granting of the interfaceadmin permission should be performed exclusively by Stewards.
To accommodate that, please remove bureaucrat's capability to grant and revoke the permission locally.
Note also that we (T&S I believe) should inform the communities likely to be most affected by this change (that is, the ones who most frequently apply IA locally) - frwiktionary, commons, dewiki, srwiki, meta, hewiki, wikidata, zhwiki, enwiki and frwiki. We'll work on that.