The Brave project is making a web browser that contains many features that have only been available as browser extensions until now. These include an ad blocker, tracking script blocker, and "HTTPS Everywhere" capability. Browsers like this have come and gone (Pale Moon, many obscure WebKit front-ends like surf), but Brave may be able to gain enough traction to be influential. We'll see. The project was co-founded by Brandon Eich in 2016.
I'm not necessarily paranoid about my unencrypted data on the web, or being tracked - I don't use a VPN service but I've been thinking about getting one. But for anyone browsing the web, I can't imagine a situation where you would want to look at an ad, communicate with a tracking script, or opt to use HTTP instead of HTTPS. Brave has the right idea because these features should just be built-in to the browser.
Google Chrome has been described as a "botnet" (I've heard that Iridium is better). Firefox's not-quite-mainstream status means that it often gives in to the status quo through fear of losing relevance, like including annoying DRM software. I don't know if Brave includes DRM software, but I can already see that removing stakeholders from the equation means that Brave can do things its own way. To the Brave project, that means taking away a lot of the features/bugs that Internet users have come to perceive as "normal". New projects like this have the freedom to set the standard.
Brave uses Chromium's Blink engine for displaying web pages, and puts its own user interface on top of that. I've been using Brave as my main browser for a week now and it doesn't have any major quirks, and it's noticeably faster than Firefox. Because it uses a lot of Chromium's UI components, I can imagine doing web development with Brave, but I think I will still be using Chromium as well for a while.