I still use the mouse to switch between tabs. I learn here that:

• the first 8 tabs can be switched with Command + <n> / Alt + <n>
• command + option + Arrow right or left / Ctrl + Alt + Up / Down to switch between tabs around

It's the 20%/80% result I was searching for.

Super + H

Ok

5. Select all occurences with Ctrl + shift + l
6. Delete a line ctrl shift + k
   I used to ctrl + x for it. But this copy the line to the clipboard. This side effect that we don't want in this case...

And others

Les raccourcis de firefox