Ref T12845. This move 'set' options (a set of values).
Set, deleted and mangled 'set' options from CLI and web UI.
Just remove unused variable and this is g2g.
Technically, there's no such thing as a JSON set?
This took a minute to grok, but this is because our set type is really just a regular JSON list that gets converted into a PHP array that maps all keys to true, right?