Could you please explain exactly what it does in the docs?

[toddobryan]

Based on the examples, I think it removes a starting bare newline, and then removes the number of whitespace characters on the first line that starts with whitespace characters. Or does it remove the number of whitespace characters on the line with the fewest leading whitespace characters?

A quick summary of what the algorithm is would make it easier than having to look in the code or try stuff.