For a moment I thought we could improve further if we rephrase "symbols with special meaning" as "reserved characters", which are defined in section 2.2 of the RFC. But that set is broader than what actually needs to be encoded for correct interpretation by our parser.
At the same time, we could still be more specific if we would say "delimiters" instead of the generic "special meaning". Should we then provide an exhaustive list of delimiters or is it clear enough like that? For example, the whitespace doesn't need to be percent-encoded (it doesn't hurt as you might be able to spare the quoting if using it as an argument to a shell command), while the "equal sign", when used in the query string part, does need encoding.
