Is the console not working?

Hi guys!

I wanted to activate the old design for YouTube. Opened the console, entered the command, pressed the input and nothing happens.

Here is the result on Firefox:

Снимок_экрана_от_2019-07-24_14-29-44

After deleting files:

  • librewolf.cfg
  • defaults/pref/local-settings.js
  • distribution/policies.json

The YouTube style has already been switched, but sending the command is still not working.