(If you search, you can find a post I made last year on editing defaultpartnercontent.json to accomplish this.)
Use backslashes or backticks, Steve:
`default_partner_content.json`or
default\_partner\_content.json🙂
In Chrome I always used 'y' for youtube and in Opera it is reserved for Yandex.
Well, that's gruesome, of course, but why not try "u", or "U":idea: