At the last Mozilla company meeting, at the all-company plenary, we had an employee reintroduce herself under her new identity. It seemed kind of normal, which struck me, as it wasn't that long ago that something like that in an entirely professional setting would have been... well, not normal. It's easy to only pay attention to bad changes and not realize how quickly good changes are happening.
I believe there are some LGBTQ social groups as well.
To the contrary one LGBT person I knew felt that Brendan supported her (in a conflict that involved her identity) when her own management did not (this was before he was CEO). I never heard any and anecdotes otherwise, and while I'm not particularly well connected I did ask some of the people who were outspoken against him.
I believe there are some LGBTQ social groups as well.