contentForBrief

Brief comment section, usually displayed as a summary/preview.

For instance, when listing all functions of a class on one page, it'll be too much to display complete documentation for each function. Instead, a small brief is shown for each one (i.e the first paragraph or some other important information) - the user can go to the dedicated page for more details if they find the brief interesting.

Tag-wise, it would make sense to include Since Kotlin, since it's important information for the users of stdlib. It would make little sense to include @usesMathjax here, as this information seems to be more specific and detailed than is needed for a brief.