Firebug should display  

[dippas]

I was coding a new website, in a very beggining and I have a extra space that I couldn't figure it out by using the firebug, until I look my source-code and there it was the   that I used just for a test and I forgot to deleted. So I think it should be good to know when there is a   while using firebug.

[Sebastian Zartner]

There is already such an option called Show Entities As Names that does the trick. See the following screenshot:

Sebastian