Invoque o Element Inspector usando Ctrl + Deslocamento + I ou clicando no item de menu apropriado:
Agora,escolhaumelementonapágina(opcional):
Ao clicar no botão 3D, você terá a visualização 3D desejada:
Nãohábotão"3D" / Não funciona. E agora?
O Firefox usa o WebGL para a vista 3D.
No meu entender, esse recurso também estava disponível anteriormente na forma do addon do Tilt . O blog diz:
Available as an addon
The latest version of Tilt can be found on Github, but you can also download Tilt as an addon from addons.mozilla.org.
For compatibility, Tilt requires WebGL capabilities. Go to get.webgl.org to check availability and troubleshoot any issues. The current version works with Firefox 6.0 to latest 10.0 Nightly releases (latest Nightly builds now also support WebGL anti-aliasing, working great with Tilt).
To start Tilt, hit Control+Shift+M (or Command+Shift+M if you’re on Mac OS), or go to Web Developer -> Tilt, available in the Firefox application menu (or the Tools menu on Mac OS). You can modify this hotkey (and other properties) from the Options menu after starting Tilt.