Iceweasel: vanilla Firefox rebranded or modifed

[Dimitris Arvanitis]

Hallo!

I know this question was raised several times, I searched around in the
internet, but I didn't find a definitive answer, especially no recent
one.

So I would like to know: Is Iceweasel "only" rebranded or is it modifed
as well? If the latter one: Where can I find a list of modifications?
Recently, Mozilla has been critizised for their cooperation with Google
and introducing connections and data transfers from Firefox to Google.
So it would be highly interesting if those connections to Google are
also being made in Iceweasel or if they have been removed.

Best regards,
Dimitris