Hacker News Reader

https://bugzilla.mozilla.org/show_bug.cgi?id=1366287

The open issues this bug depends on is a pretty good list of bigint-related performance enhancements that haven't been implemented yet.

Looks like they are using big integers, which I'd guess isn't something that comes up a lot, so probably hasn't been optimized for too much.

It is pretty new, and as you mention not many websites use them yet, so I'm sure there are more important optimizations the Firefox team is focusing on for now.

What is benchmarked here is basically the performance of the division operation on big integers and does not represent the general performance of a browser for everyday tasks.