You have to click on the "+" to open a new tab in current Browser or right click link and open in new Tab. Beyond this functions that would be the use of Addons that add "Tab" functions - if they have them to do what your asking for.

I suppose you could add the Home icon to your toolbar and then middle-click the Home icon to open a new blank tab. Just make sure the Homepage settings is set to Blank Page and not the default Firefox Home.

https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars https://support.mozilla.org/en-US/kb/how-to-set-the-home-page

Note that the '+' new tab button is customizable and can be moved to another toolbar (Navigation Toolbar) via the customize page if that is what you want. You can middle-click or double-click in free space on the Tab bar to open a new tab.

• https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars

You can middle-click a link to open this link in a new tab. This also works in the Tab history list (right-click or hold the mouse left button on either Back or Forward button).

There are two prefs on the about:config page that determine where a new tab is opened:

• browser.tabs.insertAfterCurrent false
• browser.tabs.insertRelatedAfterCurrent true
• https://support.mozilla.org/en-US/kb/about-config-editor-firefox