What I mean by universe is the fictional universe that the character or location is in. For example you can see it in use on these pages: Joan Watson, The Brownstone.
This makes things clearer for the casual reader - who can clearly see where a character or location comes from. It also makes things easier for us - we can easily stick to an in universe style without worrying about that issue.
If the line isn't used it will automatically stay blank, and if the location is for more than one fictional universe (say for example our page for London) then it should stay blank.
The style I've been using to state the originating universe is: Character from ? or Location in ?
If anyone has any questions or suggestions for improvements then please don't hesitate to leave a comment below.