Since 2016, a new version of Firefox has come out every six-to-nine weeks. Mozilla occasionally markets specific versions more heavily than others, such as their Quantum branding with Firefox 57+, and it seems like Firefox 67 is one of those above-average instances.
Several performance improvements were targeted for this release. The first improvement mentioned in the blog post is focusing on important tasks. Sites like Instagram, Amazon, and Google will apparently search 40-80% faster because less-important scripts are pushed aside. They also looked for instances where code was loading senselessly, such as auto-fill on a page with no forms.
Firefox 67 will also freeze old tabs when device’s available memory drops below 400MB. The blog post states that this was a defined threshold. I’m curious how they came up with that figure. Unfortunately, the blog is more for a general audience than a technical one. They do not state what they were specifically optimizing for, such as preventing swaps to disk.
If Firefox is your main browser (like mine) then the new version is a Help -> About Firefox click away. If it’s not on your computer, then it might be a good time to give it another try.