I found this article,

https://support.mozilla.org/en-US/kb/reset-preferences-fix-problems#w_solution-1-refresh-firefox

and reset Firefox. It fixed it, the Pocket button is now there, but that doesn't seem to me the right way, specially if other people have lots of ad-dons (I didn't have any).

Had you waited for somebody to post an answer, they might have told you to click on the three dots, next to the bookmark star at the right end of the address bar ......

Or they would have given you this link : https://help.getpocket.com/article/942-where-is-the-pocket-button-in-firefox

But you did a great job figuring it out all by yourself - well done  !

Happy112 said

Had you waited for somebody to post an answer, they might have told you to click on the three dots, next to the bookmark star at the right end of the address bar ...... Or they would have given you this link : https://help.getpocket.com/article/942-where-is-the-pocket-button-in-firefox But you did a great job figuring it out all by yourself - well done  !

I know. I don't know if Happy112 will be notify of this new reply, but for everyone out there, this issue is extremely weird. Even when I pressed the 3 dots, there was no option for the Pockeet button. I mean, why? Of course I solved the problem, but I really would like to have a dev or someone to explain what happened.

If the Pocket icon didn't show when you clicked the three dots icon and wasn't in 'Customize' either - I can only think of one reason :

After you enabled Pocket in 'about:config' - maybe you forgot to close and then restart Firefox, in order for the change to take effect  ?

And if that's not the case, then doing what you did (Refresh) was the right thing to do  !

You should mark your own post (where you told us how you solved the problem) as Chosen Solution  !