These are the explicitly grouped defines.
Not grouped defines.
These two constructors are grouped and this is the comment for them.
This constructor will go in a separate section due to this separate documentation.
These functions are explicitly grouped.
These functions have no naming similarities but since there is no blank line nor comment between them, and there is a single comment beginning with a heading, they go into their own section.
These two are grouped because the name is the same, even though there is no explicit heading.
These two are not grouped because there's no heading and the names are not the same.