The docs for "use:" are not clear

[viridia]

There's a pattern that I sometimes see in documentation, where an author will describe the motivating use case, and example usage, while forgetting to actually state what the function does. (This is still better than the inverse, which is more common: explaining the solution without ever stating the problem).

The docs for use: are an example of this - it talks about why and where you might want to use this directive, but it never actually describes what effect the directive has. And unfortunately, I am not able to deduce the functionality by looking at the example code - what I read just makes no sense to me.