Back around version 3.x and before of Firefox there was a V symbol (i.e. a down pointer) next to the < (Back) button that would provide links back to the last few pages viewed before the current one in the same TAB.
I used to find this very useful if one wanted to go back to a page before, for example, filling in a form. Using the Back button produces all those warnings about having to resend information.
This has disappeared in current versions of Fifefox, has it gone for ever?