::before/::after + flexbox in MDN

Question

I see the following news item on MDN CSS homepage:

Gecko\'s support of flexible boxes has been adapted to match a recent specification clarification:

Answer 1

This was implemented in bug 867454. Not implementing it was a mistake, as comment #0 tells.

The spec says:

The contents of a flex container consists of zero or more flex items: each in-flow child of a flex container becomes a flex item, and each contiguous run of text that is directly contained inside a flex container is wrapped in an anonymous flex item.

And that does include ::before/::after pseudo elements (at least the mozilla folks interpret it this way now, and I'd concur).

"Firefox 23 for developers" also features this information, explicitly referring to ::before and ::after as "in-flow".

In-flow ::after and ::before pseudo-elements are now flex items (bug 867454).