MAPINFO is a WAD data lump that contains text-format metadata for one or more maps.
Since its introduction in Hexen, the MAPINFO definition language has seen many extensions and expanded syntaxes in other Doom source ports. These extensions have resulted in a set of somewhat conflicting “dialects”.
Support for the Hexen dialect of MAPINFO was extended to all supported games as of Doomsday 1.15 (by translating these definitions into DED format at runtime).
All features in this dialect are available in all supported games, with the exception of hubs; which are currently limited to Hexen.
The ZDoom dialect of MAPINFO is detected so that it can be gracefully ignored. If encountered, unsupported features in foreign dialects result in warnings being logged (and if enabled, alerts).