BRAT is a diet where one lives on a strict Leberkas-only diet, with variants like Pizza, cheese, wild garlic, or pumpkin-bacon Leverkas being allowed. The Leberkas must be served with mild peppers and sweet mustard in a bread roll.

Originally called “kasln”, the diet was quickly taken over by the Piefke, which quickly named it Brät(-Diät), stemming from the fact that they desecrate Leberkas by calling it “Fleischkäsebrät”. Further, as it gained further international succes, as Anglo-Saxons cannot wield the might of unlauts, its name was simplified to BRAT.

Additionally to the other two replies, Brave also injected referral IDs to an URI when you directly typed it in. Allegedly it was a mistake and they put it behind a toggle:

• Article: https://www.technewsworld.com/story/brave-browser-caught-redirecting-urls-for-cash-86701.html
• Their blog: https://brave.com/blog/referral-codes-in-suggested-sites/

Also, per default the new tab page shows advertisements in the background. Firefox does also show ads on the new tab page in the link grid, so it’s a bad thing both do and you can disable it on both. But with an almost-full-window sized ad Brave managed to make that worse still.