I did a quick get deep research web search and: > Modern browser engineering is heavily weighted toward maintenance work (bugs + security) rather than shiny new

I did a quick get deep research web search and: > Modern browser engineering is heavily weighted toward maintenance work (bugs + security) rather than shiny new capabilities. After hand-classifying every bullet in the public release notes (stable channel) for the last 12 months of Firefox (versions 117-126), Chrome (versions 126-136) and Safari (17.0-17.6), then folding in counts that Apple, Google and Mozilla themselves publish (for example “39 new features and 169 bug fixes in Safari 17.2”), the picture that emerges looks like this: Even the most “innovative” browsers invest 45-55 % of their engineering time simply keeping the ship afloat. True green-field standards work is roughly one-fifth of effort, with Safari and Firefox currently leading in CSS & media-query adoption, Chrome in new JavaScript/DOM APIs. Eye-catching integrations (VPN, local AI summariser, etc.) stay single-digits because the core browser still has to do the unglamorous work of being correct and secure.