Suppose I'm the first person write a proper Doxygen comment for a source file. Suppose also that there have been multiple contributors to the file - original author, previous maintainers, current maintainers, people who contributed a function, or just a minor one-liner bug fix.
What's an appropriate way to list them (using the @author / @authors doxygen tag), along with their roles? (Or - should I not list their roles?)
Version control is the best place to find a list of maintainers and contributors. Version control is also the best place to find out why code was changed. It does not matter whether you use Git, Subversion, Mercurial, or any other kind. Changes to files should be tracked by a proper version control system.
This negates the need to list authors in Doxygen comments because version control associates changes with the person who made them. Code comments should explain how to use the code without resorting to reading source code. You can always extract a list of maintainers from the commits in version control. Knowing the author doesn't tell me how to call a function, or for what purpose a certain class exists. Listing authors in comments is an artifact of a bygone era before version control systems were widely-used.
It has been my experience that author roles or job titles have been less important than who made a change, why it was made, and what their email address is so I can contact them if I have questions. I wouldn't worry about roles at all in version control or Doxygen comments.
