It is parsed by a recursive-descent parser that is built into doxygen. The file may contain tabs and newlines for formatting purposes. The statements in the file are case-sensitive. The file essentially consists of a list of assignment statements.
Values are sequences of non-blanks.
The configuration options can be divided into four categories. Below is a list of tags that are recognized for each category. This name is used in the title of most generated pages and in a few other places. This could be handy for archiving the generated documentation or if some version control system is used. If a relative path is entered, it will be relative to the location where doxygen was started.