Hi

Firefox has not long had its 20th birthday - you can read more about this at https://blog.mozilla.org/en/products/firefox/firefox-milestones/

The 20th birthday was when Firefox version got to 1.0 Release as it ignores the earlier Releases of the web browser.

The web browser we know as Firefox has existed since it was Phoenix 0.1 released on September 23, 2002 until Phoenix 0.5 released December 7, 2002. It then had first name change to Firebird from 0.6 (May 17, 2003) to Firebird 0.7. Then as of February 9, 2004 the name changed to Firefox for the 0.8 Release and on since. https://en.wikipedia.org/wiki/Firefox_early_version_history

So Firefox is over twenty two years old now though Mozilla likes to say Firefox had not really released until it got to version Firefox 1.0 Released on November 9, 2004. The Firefox 1.0 release had the code name of Phoenix.