How can I dump the entire Web DOM in its current state in Firefox?
Looks like FireFox have replaced the DOM Inspector with a new tool that no longer has this functionality.
In the new DOM Inspector Ctrl + Shift + I there is a Console that accepts commands.
This sometimes works...
console.log(document.documentElement.innerHTML)
This gives you something you can inspect but not copy paste because of some bug...
alert(document.documentElement.innerHTML)
This works like console.log(document.documentElement.innerHTML) ought to....
document.documentElement.innerText = document.documentElement.innerHTML
DOM Inspector has a File->Save DOM As...
option.