It seems like dircategory has to come before the first node.
@parindent=0pt
@end iftex
@c %**end of header
@parindent=0pt
@end iftex
@c %**end of header
-@ifnottex
-@node Top
-@end ifnottex
@dircategory Mathematics
@direntry
* ginac-examples: (ginac-examples). C++ library for symbolic computation.
@end direntry
@dircategory Mathematics
@direntry
* ginac-examples: (ginac-examples). C++ library for symbolic computation.
@end direntry
+@ifnottex
+@node Top
+@end ifnottex
+
@finalout
@c finalout prevents ugly black rectangles on overfull hbox lines
@finalout
@c finalout prevents ugly black rectangles on overfull hbox lines