Thread:Project:Support desk/What does "raw:" do?

Over at the English Wiktionary, we're trying to figure out what the prefix "raw:" does. It was used in certain old templates, such as Template:slink, and was therefore recently copied into the major Template:head (diff / example of use)... but no-one remembers what it does. Obviously, using code without knowing what it does is suboptimal... can you enlighten us as to what it does, so we can decide if it's necessary? Feel free to reply here or post a note to Template talk:head.

If I'm not asking this question in the right forum, I'm sorry and I'd be obliged if you could direct me to a better forum.