How to add addon icon to firefox toolbar?

Question

Mozilla Firefox

How to add addon icon to firefox toolbar? In toolbar personalization, there is no such option to drag extensions to the toolbar. Googled - Googled, all the articles are some kind of dummies.

Answer 1

look/search in addon settings.
usually by default icons should be shown,
but in some add-ons, the display of the icon in the panel and / or in the context menu is
configured in the add-on itself.

Answer 2

most likely, history saving is disabled and cookies are disabled, you need to activate work in private mode in the addon settings