What is Firefox and Thunderbird?

With the release of Thunderbird 1.1 Alpha 1, the old-school spellchecker is now replaced with a smarter inline spellchecker as expected in word processing tools like Microsoft Word and OOo Writer. However, the default dictionary ironically doesn't contain the defination of Firefox and Thunderbird:

I guess it is not that hard to add these Mozilla-related words into the dictionary, right?

P.S. Obviously it is not a grammer checker. ;-P