For more information, please visit the following pages:

• Firefox
• Mozilla Foundation
• Gecko

Latest user agents (if you are looking for complete list, download it here):

• Mozilla/5.0 (Android 2.2; Mobile; rv:12.0) Gecko/12.0 Firefox/12.0
• Mozilla/5.0 (Android 2.1; Mobile; rv:12.0) Gecko/12.0 Firefox/12.0
• Mozilla/5.0 (Linux i686; rv:12.0) Gecko/2011424 Firefox/12.0
• Mozilla/5.0 (Linux i686; rv:12.0) Gecko/2008622 Firefox/12.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 11_2_0) Gecko/20171511 Firefox/12.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8.6; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.8; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.7; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Windows NT 6.0; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.4; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6.5; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.9; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.5; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.10.0; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Windows NT 5.2; Win64; x64; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; PPC Mac OS X 10.8.8; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.8; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.8; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.10.8; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.2; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.5; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.4; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Linux x86_64; rv:12.0) Gecko/2005228 Firefox/12.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.10.6; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6.2; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.0; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.1; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.3; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.9.2; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.6; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.8.6; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.2; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.5; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.6; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.0; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.8; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5.1; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.7; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Windows NT 5.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.9.1; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.3; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.9.0; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.0; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.7; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5.7; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8.6; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.0; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5.3; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.2; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.10.4; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.5; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.5.8; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.0; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.5.6; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.10.9; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.7; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.9.8; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.9.0; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.9.5; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Windows NT 5.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.7; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Windows NT 6.3; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.7.3; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.7.7; rv:12.0) Gecko/20100101 Firefox/12.0.9
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.7.3; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.9; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.0; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Windows NT 5.1; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; PPC Mac OS X 10.8.5; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.6; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.9; rv:12.0) Gecko/20100101 Firefox/12.0.6
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.3; rv:12.0) Gecko/20100101 Firefox/12.0.7
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.1; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Windows NT 6.2; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9.2; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5.1; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Windows NT 6.3; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.8.1; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6.8; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.7.9; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.9.3; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10.8; rv:12.0) Gecko/20100101 Firefox/12.0.1
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7.4; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Windows NT 6.1; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Windows NT 5.0; Win64; x64; rv:12.0) Gecko/20100101 Firefox/12.0.2
• Mozilla/5.0 (Windows NT 6.0; WOW64; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.10.3; rv:12.0) Gecko/20100101 Firefox/12.0.4
• Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20100101 Firefox/12.0.8
• Mozilla/5.0 (Windows NT 5.2; Win64; x64; rv:12.0) Gecko/20100101 Firefox/12.0.0
• Mozilla/5.0 (Windows NT 6.2; rv:12.0) Gecko/20100101 Firefox/12.0.5
• Mozilla/5.0 (Windows NT 5.0; Win64; x64; rv:12.0) Gecko/20100101 Firefox/12.0.3
• Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20100101 Firefox/12.0.0