Good video.

Brave is not built in Chrome. There is no other browser which could be based in Chrome, as it is Google propietary version of another browser: Chromium.

While anyone can take Firefox and rebrand it -Mozilla will for sure suit you if you don't- and then make any changes they can, that is not possible with Chrome.

Opera and Vivaldi are also really awesome Chromium based browsers.

EDIT: Brave is not a Chromium browser. It is an Electron app. Electron is a technology which makes easier to developers package a web page and deploy it like if it was a native app. But, yes, still Electron uses Chromium in order to show those web pages.