Im a beta tester for this product and it does use Chromium under the hood, pre-bundled with uBlock no less.

Well then it doesn't seem so groundbreaking then

i'd have liked to be a fly on the wall when they pitched this to the investors

I would like to read more about this. Do you have links?

Seeing as its a closed beta, I don't really have any links to any reading material on the app - However here are some screenshots however showing the Chromium pages within Arc Browser and some of the supporting files within the app bundle. https://imgur.com/a/DXE1x0m

Thanks for the snapshots and info.

a ui on top of chrome doesn't get you $25 million in funding and a dedicated Bloomberg article

edit: apparently it does

I'd expect the opposite. It's likely not worth funding someone to reimplement a whole browser engine instead of reusing an existing one. It would take a lot of time and money to build and maintain and you don't gain too much by having your own entirely custom engine.

There's a difference between forking a full browser (this is quite easy initially, but down the road your fork may end up being difficult to maintain) and building a new browser on top of the rendering engine (Blink here, could be Gecko or Webkit). In the latter case, the initial investment is higher, so getting to a daily driver product requires more effort. However long term that can be beneficial because you don't conflict that much with upstream changes.

Writing a new rendering engine and browser on top is totally different effort as you may guess.