• Firefox - Going down the toilet, but still preferable to the Google ones.

Notes on features and different browsers' support

• Chromium
  • No support. There used to be a plugin called 'Style Chooser', but I think it's gone?
• Dillo
  • No support
• Firefox
  • Accessed via View > Page Style.
• Konqueror
  • Apparently supports.
• Kristall
  • No support
• Ladybird
  • No support? Yet?
• Netsurf
  • No Support
• Opera
  • Apparently works, but I haven't tried.

• https://developer.mozilla.org/en-US/docs/Web/CSS/Alternative_style_sheets

• https://privacytests.org/ (don't use Brave though, please)