[joe-collins]

Should I have prefaced my own definition with "imo"? I believe that there is a common semantic core that could be encapsulated in a new element. The closest thing to a presentational demand I would include is that they be temporary.

[yyyk]

I did not mean to be overly argumentative. I just wanted to refer to the proposal as it is. There could be a case for a somewhat different proposal like yours, say if mobile does need this and implements support. However, at the moment the proposed element is defined almost entirely by presentational demands.