Several addon formats are supported by Doomsday (and Snowberry) and are intended for a variety of different purposes. Some are inherited from existing games (such as WAD from DOOM '93) where others are entirely new, designed to make the modding process easier for end users.

The following diagram explains the high-level organization of these formats and their relationship with one another:

• addon_bundle
• plugin_bundle (Snowberry extension)
• ZIP/PK3
• wad (lmp)

• ded
• deh
• info (metadata)
• manifest

• Box (a folder)

• Packages (1.15 →)