Brave search is only very recently independent, and not, as far as I can tell, 100% of the way there. While they are building out their own index, they only recently stopped augmenting their own results with Bing, and are still augmenting them with Google.

That is not fully accurate. Brave Search is fully independent - the last dependency on Bing was dropped more than a year ago, but even at the time the dependency would not have prevented Brave Search from functioning during an event like yesterday’s Bing outage - it would have resulted in a drop of quality on a subset of complicated queries, though.

The “augmentation with Google” that you mention is an optional feature that only works in Brave browser and doesn’t mean Brave Search is less independent than in other browsers (but it might mean that the quality is increased for some queries; or at least closer to Google results in these cases).

I think when talking about independence it is important to make a distinction between “dependent” which means “cannot work at all if the provider goes down” (e.g. yesterday’s outage) and “dependent” meaning that the service would continue to operate but with some amount of degradation of service. It’s a spectrum. Yesterday we saw that some services could not operate at all when Bing was down.

Disclaimer: I work at Brave.