New
#571
The new extensions button on Firefox gives users control
Here’s what’s going on in the world of extensions
I found this new extension button unnecessary and just taking up space.
And despite Mozilla saying it can't be removed* or dragged off the 'tool bar' like the other common icons such as Favorites, Reload, Home, and Download, it can be removed via a hidden about:config preference:
extensions.unifiedExtensions.enabled set to False
*Manage your extensions using the extensions button in the toolbar | Firefox Help
Can I remove the extensions button from the toolbar or customize its location?
No, it is currently not possible to remove this button or change its location. This is by design. The extensions toolbar button is now the primary user interface and allows access to per-site permissions for MV3 extensions.