Before v149 there was no menu entry to disable AI, instead

about:config (in adress bar)
browser.ml.enable (in search input field)
click ⇌ (from true to false)

 Name                    Last modified      Size  Description
 Parent Directory                             -   
 apt/                    2025-03-03 09:57    -   
 block-injected/         2023-03-30 22:11    -   
 set-firefox-ai.pl       2025-11-10 12:37  774   

• Mozilla Wiki about Firefox Nightly: visit and choose, then e.g. compiled binary
  P='https://ftp.mozilla.org/pub/firefox/nightly/latest-mozilla-central/irefox-151.0a1.en-US.linux-x86_64.tar.xz'
  curl $P | bzcat | tar xv
  ./firefox/firefox &
  • See also: .deb pakckage, beta, dev, nightly or apt repo
• try SeaMonkey, too?
• integrity & security checking
• improve your browsing with awesome userscripts
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