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 (X11; Linux i686; rv:23.0) Gecko/20130811 Firefox/23.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:23.0) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Linux x86_64; X11) Gecko/20021710 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.3; WOW64) Gecko/20072202 Firefox/23.0
• Mozilla/5.0 (Linux i386; X11) Gecko/20101710 Firefox/23.0
• Mozilla/5.0 (Linux x86_64; X11) Gecko/20040411 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130620 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130617 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0; WUID=7cf8779740be479aa7fa184ca16859a7; WTB=2938) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Linux i386; X11) Gecko/20141703 Firefox/23.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) Gecko/20171711 Firefox/23.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 11_9_5) Gecko/20191601 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/alxf-2.18
• Mozilla/5.0 (Windows NT 6.2; Win64; x64; rv:23.0) Gecko/20130410 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/amznf-3.0.20121130
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/alxf-2.19
• Mozilla/5.0 (Windows NT 6.2; rv:23.0;resident) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130813 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130813 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0; WUID=2d7d55e2cc5fe14ec1e6689cc4d670d5; WTB=2937) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0; WUID=c3c50d13e2a5f31b6dc4ba0b88f698f5; WTB=6533) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0; WUID=edeb227dcb33a83ae8eed490acfaf4c7; WTB=592) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/pNJuBjJf-2.1
• Mozilla/5.0 (Windows NT 5.1; rv:23.0; WUID=9a7ae5bed9b447b297e8dd93e683be4c; WTB=619) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130602 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0; WUID=32dcc6056a9431615cbcb19206095651; WTB=6533) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/pNJuBjJf-2.1
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130526 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:12.0) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0; WUID=320273e65026cbfa4cf7b25cb7b31ee5; WTB=2996) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/alxf-2.19
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130813 Firefox/23.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:23.0) Gecko/20100101 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Chrome/23.0.1271.64 Safari/537.11
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130616 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130517 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20100101 Firefox/23.0 WebMoney Advisor MRA 5.4 (build 02647);
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20100101 Firefox/23.0 FirePHP/0.7.2
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20100101 Firefox/23.0 AlexaToolbar/pofWyHsf-2.2
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130608 Firefox/23.0,gzip(gfe)
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130607 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; WOW64; rv:23.0) Gecko/20130520 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130527 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130508 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130415 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130607 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130617 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130619 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130610 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130620 Firefox/23.0
• Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:23.0) Gecko/20130616 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130619 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130520 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130827 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20130504 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130614 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130601 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20130511 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130621 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; Win64; x64; rv:23.0) Gecko/20130410 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.2; Win64; x64; rv:23.0) Gecko/20130425 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130611 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130602 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130619 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130611 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130523 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130620 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130615 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130617 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/39237369 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130607 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130528 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130606 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.0; WOW64; rv:23.0) Gecko/20130528 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130606 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130623 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130624 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130501 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130612 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; WOW64; rv:23.0) Gecko/20130622 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20130425 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130610 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130608 Firefox/23.0
• Mozilla/5.0 (Windows; U; Windows NT 6.1; pl; rv:23.0) Gecko/20100101 Firefox/23.0 (.NET CLR 3.5.30729)
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130827 Firefox/23.0
• Mozilla/5.0 (Windows NT 5.1; rv:23.0) Gecko/20130615 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130624 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130609 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130527 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130616 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; WOW64; rv:23.0) Gecko/20130606 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:23.0) Gecko/20130503 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; rv:23.0) Gecko/20130608 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.1; rv:23.0) Gecko/20130606 Firefox/23.0
• Mozilla/5.0 (Windows NT 6.2; WOW64; rv:23.0) Gecko/20130607 Firefox/23.0