[OversouL]

At first i didn't understand what the difference was so I Google'd it and this is what I found:
Firefox Nightly is an Alpha
Firefox Aurora is a Beta
Firefox is a release.

After every new update, Nightly turns into Aurora, Aurora turns into the Release and then they make a new Nightly for the next update. So what you are seeing right now in Aurora is what is to come in the next Firefox update, just buggier.

Oh, so that's it. I kinda liked the theme.