I don't use mobile browsers much, but one thing I wish FF could do is give me an easy way to move a private tab into a regular one. I have private tabs enabled by default to not pollute my history with garbage but every once in a while you want a link to open regularly and you can only do it my manually open the address bar, selecting the URL, copying it, closing the tab, switching to non private mode, open a new tab, paste the address, confirm. This is excessively long and annoying, even for mobile phones and their terrible multitasking issues.