firefox process itself using 100 percent cpu

No tab in about:performance shows anything but minimal usage. No process in about:processes shows anything except the “Firefox” process itself.

On Firefox Browser 105.0 (64-bit) on Debian GNU/Linux bookworm/sid, Gnome 42.4 with Wayland. Dell Inc. Precision 5540 32 GiB memory, Intel® Core™ i9-9880H × 16, Software Rendering / Mesa Intel® UHD Graphics 630 (CFL GT2).

Pretty sure this started a Firefox version ago but i’m only starting the documentation now.

On the plus side, it’s getting chilly and Firefox is making my laptop work as a space heater just in time.

Fruitless research

Firefox consuming 100% CPU; about:performance shows nothing - Ask Ubuntu

Firefox always uses 100% cpu idling after some time - Linux Mint Forums

(2016) Firefox driving me nuts taking up 100% of the CPU