Ah. I parsed that sentence incorrectly.

I read it like this:

> Your program produces output to be read by another (eg: a browser), or (implements a network protocol, and relies on the other party's software to be significantly tolerant to spec violations)

instead of like this:

> (Your program produces output to be read by another (eg: a browser), or implements a network protocol), and relies on the other party's software to be significantly tolerant to spec violations