Why does firefox take up 3 gigabytes of RAM?

Question

Browsers

I closed almost all the tabs, opened the dispatcher, I see he is still eating like crazy. I'm trying to close it,

I've heard such a modal about hangouts, but how does it slow down the browser? Of the extensions, only ublock and fireshot (screenshot) are active.
(On board arch xfce)

Answer 1

FF gets crazy at times and just needs to be restarted. This manifests itself in various glitches, for example, for me, the face of Synology stopped responding :)

Answer 2

Appendix? Website with flash player?