Firefox 3.1 beta 3 is expected to arrive this week. If you’re running the current version of Ubuntu Linux, this new Firefox edition (codenamed ‘Shiretoko’) is already easily installable via an unofficial package repository.

However, due to an oddity in Ubuntu’s default font settings, the fonts in Firefox 3.1 look spindly and kinda bizarre (though in no way unreadable) on Ubuntu Intrepid (8.10) machines. (The same apparently happens in the nascent Jaunty (9.04) version of Ubuntu; it’s being treated as a bug.) This issue has been noticed over at Ubuntu Forums but no simple solution was forthcoming. Until now.

Here is a simple fix for the spindly, messed-up fonts you see in Firefox 3.1 if you install it under Ubuntu Intrepid (8.10). In a Terminal window, issue these commands:

sudo mkdir /etc/fonts/conf.disabled
sudo mv /etc/fonts/conf.d/10-* /etc/fonts/conf.disabled
sudo mv /etc/fonts/conf.d/53-* /etc/fonts/conf.disabled

You’ll need to restart X (press Control-Alt-Backspace after saving any unfinished work) for this to take effect. I’ve done this on both desktop and laptop machines. It’s fixed the Firefox 3.1 display issues, and I’ve noticed no side effects. If you experience side effects or wish to undo this change for some other reason:

sudo mv /etc/fonts/conf.disabled/* /etc/fonts/conf.d

As for Firefox 3.1 itself: Firefox 3.0 is great, but has always felt sluggish on my Linux boxes any time I’ve had more than two or three tabs open. (Yes, I have tried the various about:config voodoos you can find via Google; they have not helped.) With Firefox 3.1, I am experiencing dreamlike performance gains. The browser responds adroitly even with a couple dozen tabs open. The functional improvements in 3.1 strike me as minimal so far. What I’m noticing is the speed.