Over at TheNextWeb, it’s been reported that Mozilla has “quietly killed” the 64-bit build of Firefox for Windows. There has never been a stable release, however. The 64-bit build has been limited to Mozilla’s Nightly and branch builds — like the Firefox UX build where the new Australis theme first appeared. TNW’s Emil Protalinski noted in his post that Firefox engineering manager Benjamin Smedberg ”had declared that the 64-bit version of Firefox for Windows would never see the light of day,” but that’s not actually the case.

Indeed, the title of the related Bugzilla item tells a different story: “Disable windows 64 builds for now” (emphasis added). Mozilla hasn’t come out this week and said that there is no future for 64-bit Firefox on Windows. Instead, it’s a question of whether or not there’s enough return on the investment to continue offering the x64 Nightly builds to testers.

According to some in the community, as much as 50% of Mozilla’s testing base was browsing with the Windows x64 build. Those folks can, of course, move safely back to the 32-bit build as long as they don’t need a browser that can address more than 4GB of memory. That should only pose a problem if you keep a massive number of tabs open in any given browsing session, say 50 to 100. Those with more mundane needs that just want early access to bleeding-edge features in Firefox should be able to run the 32-bit nightly builds without noticing any real difference.

Smedberg notes several reasons that the decision was made. Plug-ins are currently a major headache — some common ones lack a stable 64-bit build, and some of those that do aren’t working correctly because Firefox lacks certain required features. That’s leading to additional freezing and crashing. Mozilla’s crash stats system also can’t easily tell which reports are from 32-bit users and which are from 64-bit users, which causes additional grief for coders who are trying to correct issues.

“The needs of the many must outweigh the needs of the few or the one,” said a wise, pointed-eared man. Mozilla needs to focus on 32-bit builds of Firefox for Windows because that’s the biggest, most critical piece of its user base.

Firefox x64 isn’t dead, it’s just going to disappear from the nightlies at some point in the near future. It will be back some time later in 2013, but in the meantime Windows users should know that there’s an alternative which doesn’t require leaving Mozilla in the lurch. Check out WaterFox or Palemoon: both are 64-bit custom builds of Firefox for Windows.

More at TNW, Bugzilla, and Google Groups