What you posted is a date/time number in epoch format (1353791192: Sat, 24 Nov 2012 21:06:32 GMT)

You can see some data on the Help > Troubleshooting Information page.

• browser.startup.homepage_override.buildID
• browser.startup.homepage_override.mstone

You can also click the about:buildconfig link and proceed to the Built from http://hg.mozilla.org/ link.

Your UserAgent shows this - Mozilla/5.0 (Windows NT 6.2; WOW64; rv:20.0) Gecko/20.0 Firefox/20.0 - which is Firefox 20.0.

Using Help > Troubleshooting Information - > Build Configuration will give you additional information about that build.

Thanks to cor-el I found the builds, but my goal is to download one of them. The newest zip doesn't give any programs to open, so what page should I go to to download these builds?

If you download a ZIP build then you need to extract (copy) the contents of that archive to a folder in the Firefox program folder

• (32 bit Windows) C:\Program Files\Mozilla Firefox\
• (64 bit Windows) C:\Program Files (x86)\Mozilla Firefox\

Any particular reason why you want to install a Nightly Firefox build?

Note that these builds update daily and are meant for experienced users that know how to deal with issues.

There is a daily thread where you can discuss issues with the latest Nightly build on the MozillaZine Builds forum.
You need to register on the MozillaZine forum site in order to post at that forum. See http://forums.mozillazine.org/viewforum.php?f=23

I've got the problem solved on my own going off your first answer. Thanks and don't worry, I know what I am doing :)