Your Firefox User Agent or build ID contains a lot of information about your browser as well as your operating system. Here is break down on what is in your User Agent:
Mozilla/MozVer (Platform; Security; SubPlatform; Language; rv:Revision[; Extension]*) Gecko/GeckVer [Product/ProdVer]
- Mozilla/MozVer ~ All Firefox build IDs start with Mozilla/5.0. Simply put this means the browser meets the standards to be Netscape 5 compatible. This was the first Mozilla based (never released) version of Netscape.
- Platform ~ This is the operating system (but not the version). Possible values include:
- X11 (Linux)
- Security ~ This is the encryption strength of the browser:
- U: Strong Security, 128-bit encryption (USA)
- I: Weak Security, 40-bit encryption (International)
- N: No Security, No encryption
- SubPlatform ~ This is the version of the operating system.
- Win 3.11 – Windows 3.11
- Win 95 – Windows 95
- Win 98 – Windows 98
- Win 9X – Windows ME
- Win NT 4.0 – Windows NT 4.0
- Win NT 5.0 – Windows 2000
- Win NT 5.1 – Windows XP
- Win NT 5.2 – Windows Server 2003 and XP Pro x64
- Win NT 6.0 – Windows Vista
- x11 Linux:
- Linux [Version] Hardware
- FreeBSD Hardware
- NetBSD Hardware
- SunOS sun4u
- PPC Mac OS X
- PPC Mac OS X Mach-O
- Intel Mac OS X
- Language ~ standardized language identifier, Firefox is available in several different languages. The two common English language builds are:
- en-US = English United States.
- en-GB =English Great Britain.
- rv:Revision ~ This is the version of Gecko, the browser engine.
- Gecko/GeckoVer ~ This is the date in YYYYMMDD format the revision (or version) of Gecko was was compiled, not necessarily the date it was released
- Product/ProdVer ~ The name and version of the product. Some of these include:
- Deer Park/1.5
- Gran Paradiso/3.0a1
Below is the user agent as found via Help, About Mozilla Firefox for my current version of Firefox:
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:18.104.22.168pre) Gecko/20061223 BonEcho/22.214.171.124pre
I am running a Mozilla product compilable with Netscape 5.0, on a Windows platform, with high 128-bit encryption USA security, on the Windows NT 5.1 (XP) subplatform, using an english-US language. My current build of Firefox is based on the 126.96.36.199pre revision of Gecko which was compiled on 12/23/2006. The product name is BonEcho (nightly build) and the version I am running is 188.8.131.52pre.
Now you can see how valuable your user agent/build ID is for troubleshooting, especially when people are not even sure what operating system they are using much less which version of Firefox.