I posted this in supporters regarding Mozilla Bot:-
For those who have not got a subscription get one (kidding - well sorta)
Bit more information on this bot as far as I can see.
Yes - it does enter pages into the index - I have had problems with my site so I have not seen as much Googlebot activity as normal - anyway the last time I saw Mozilla Googlebot was in November when their was a massive crawl.
I still have some pages going back to November in the cache (supplemental now - but in the index) and these were fetched by Mozilla Googlebot - they have the exact time date stamp of when Mozilla Googlebot visited.
So for me it does enter pages (how quickly and whether all pages I dont know)
Also looking at what Mozzila Bot has done over the last few days - it has fetched new pages - at one stage I thought it was just going over old ground but it does look like it is picking up new pages.
The Mozilla Bot finished earlier today (unless it comes back later) - it was under ip 18.104.22.168
I dont know if the pages from November were always supplemental or whether they have become supplemental due to age (I think the age factor is more likely though)