In converting Special:Log to HTMLForm for T117737 the LogEventsListGetExtraInputs hook now optionally takes a $formDescriptor array. At some point we should remove the old $input string.
rMW38756eae46a8: Special:Log: Convert to HTMLForm
rMW2dce53c5ae71: [wip] LogEventsListGetExtraInputs: Allow both string and array