You can add extensions to the toolbar using Pin to toolbar menu option.

See Manage your extensions using the extensions button in the toolbar

Thank you for this - but I don't think you can see the actual extension until you click on the jigsaw-piece generalised extenion button. You used to be able to pop an extension - like Tiny URL, which i find particularly useful - onto the toolbar, and access it with one click, not two.

You can access TinyURL in one click if you pin it to your toolbar.

Firefox 109 comes with the Extensions button in the Navigation Toolbar as the new way to manage your extensions. The panel that opens if you click the Extensions button (puzzle piece icon) serves as overflow area for extensions you install. The legacy chevron (>>) overflow area still exists but is only used for built-in toolbar buttons as found in the Customize page.

In the Extensions button panel, you can click the gear icon next to an extension or use the right-click context menu to pin the extension to the toolbar (Pin to Toolbar). To (re)move the extension from the toolbar back to the Extensions button panel, you can use "Unpin from Toolbar" in the right-click context menu.

More Information:

• https://support.mozilla.org/en-US/kb/extensions-button