How does left-foot breaking works?

I'm learning to drift and I saw a video talking about left-foot breaking. I saw it, I tried it and it worked! But I don't know how and why it worked.

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I know that one of its purpose is that when you're accelerating mid drift, pressing the brake pedal makes the car gain more angle, but I'm still not sure when to use it.

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So, can anyone help me out? I'll ask to please correct me if I said anything wrong.

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Any help is truly appreciated! 😁