Constant disk activity when Firefox is idling on MacOS 13.6

[Fernfire]

I have MenuMeters in my menubar displaying disk activity and I noticed that there is constant disk activity (reading and writing every 5-10 seconds) when Firefox is idling. The disk activity stops if I quit Firefox. What is this activity related to?

M2 MacBook Air running 13.6.4 and Firefox 123.0.

[articfox]

Firefox writes more to disk than than all the other apps and the system itself.
And I confirm, like you said even when it's idle, it is writing to disk all the time.
I tried to disable disk cache and it didn't work.

I really think I'll stop using Firefox just because of this.