I notice that in the physics field, there are sometimes co-first authors, both names being followed by a footnote saying "These two authors contribute equally."
Even though explicitly labeled as so, one name still comes before the other. Also, as far as I know, the one believed to contribute a little bit more goes first. Hence, these are actually not real co-first authors.
Imagine in some journal with an author-title header on every page. The name of FirstAuthorB, the co-first author who comes after FirstAuthorA, will not be shown, as in
FirstAuthorA et al.: Paper Title
So is there some other generally accepted ways to truly display two first authors as completely equal?