It looks like Firefox 64-bit may have launched to the stable channels. I was poking around earlier when I saw 42.0 b1 x64 had landed. I checked for a stable build and when I added 64 after win, I got a successful download.

https://download.mozilla.org/?product=firefox-42.0-SSL&os=win64&lang=en-US

It sure looks like a stable build, is this official? I hope so!

Yep, Firefox 42 is available for Win 64, it is an official build. 

On this Bugzilla page - https://bugzilla.mozilla.org/show_bug.cgi?id=1181014#c24 
this was posted: "We won't update the download page with Windows 64 builds for 42. We are waiting for some partner
changes before making that public. However, the binaries will be available on the ftp for testing:" - followed by
a link. 

I didn't post anything about it since Mozilla really frowns on sending the public to their ftp site, it
can't handle the traffic. I wasn't quite sure I believed it anyway - Fx 37 was originally the target,but it got
pushed back repeatedly. But, after months of delay, it's really here - though it's hidden where most people won't
find it.

 

Your link isn't to the ftp site, though. Looks like they've uploaded it to the regular download servers, but aren't providing links to it.yet.

 

Don't know how I wound up with 2 different fonts, I didn't change the font. Weird.

 

Sweet, absolutely love it. I'll start recommending it to people over the 32 bit version.

They'll be real impressed when you tell them how to get the "secret" 64-bit upgrade.

 

I really don't understand what the holdup is. It's been in the works for a long time - who are these partners that still aren't ready for it? It's hard to imagine how anyone could be that slow and stay in business.