Commenting a definition

It is hard to use search engines to search for webpages talking about the topic of comments, as nearly every page has a comments section! My apologies if this topic has already been discussed.

In traditional code, line-by-line comments provide an annotation which makes it easier to "read" the code, even if you didn't write it, or if you wrote it a long time ago. I often find it difficult to document what my definition is doing on such a fine-grained level. I can label groups, which is a sort of analog to the description of a function in code. But I often find I want to leave a little note about what a single component is doing. For example, why do we need to shift the paths right here, or what is this path mapper component really doing. The best tools for this seem to be either a scribble or a panel, both of which are cumbersome for something this fine-grained. The closest thing, maybe, is the option to rename components, but I've found that to be confusing on components which aren't just simple containers.

Could there be a way to add comments to individual components through their context menus? Maybe they would display on hover, or on zooming, like the profiler. I think this could be a very useful tool for complicated definitions, especially if someone who didn't write the definition needs to have a detailed understanding of how it works.

Thoughts?