Is there any reliable extension, or any way whatsoever, to view two pages side by side in one Librewolf window?

No, I do not want two separate windows (one, because I do not need two identical-but-short top menu bars, and two, because Librewolf saves my last session's tabs, and if I close the wrong window, it will reopen the last session with one tab as opposed to a dozen or whatever).

I've looked through extensions, I DDG'd the question, haven't found anything.

But it seems like such a basic thing, I must be missing something, right?

#librewolf #librewolfbrowser #firefox