Due to bug 43221 and Gerrit change I1a3c7ac6, the format of the "details" for some log events will be changing. In particular, any event with details that were returned with a key resembling "4::foo" will now be returned under a key of simply "foo".
This change will be deployed with 1.21wmf7, which is scheduled for today on mediawiki.org, test.wikipedia.org, and wikidata; 7 January for non-Wikipedia sites; 9 January for enwiki; and 14 January for the other Wikipedias.