You see the orange (on Linux gray) Firefox button if the Menu Bar is hidden. If you need to access t

You see the orange (on Linux gray) Firefox button if the Menu Bar is hidden.
If you need to access the hidden Menu bar then press F10 or hold down the Alt key to make the Menu Bar appear temporarily.

You can right click the orange Firefox button to open the toolbar menu or use (F10) View > Toolbars.

Click the Menu Bar entry to make the Menu Bar visible.

Click "Tabs on Top" to remove the check mark and place the Tab Bar at its original position just above the browser window.

You can find the Home button at the far right end of the Navigation Toolbar.

You can open the Customize window via "View > Toolbars > Customize" or via "Firefox > Options > Toolbar Layout" and drag the Home button to its previous position.