In the Unreal Tournament games, the list of maps displayed for a particular gametype is determined by the map prefix on the filename. So if you want a map to appear in the game interface, its filename (up to the file extension) must be of the form:
PREFIX-ActualName
The prefixes are:
- AS = Assault (UT, UT2004)
- BR = Bombing Run (UT200x)
- CTF = Capture the Flag
- VCTF = Vehicle Capture the Flag (UT2004)
- DOM = Domination (UT), Double-Domination (UT200x)
- DM = Deathmatch
- ONS = Onslaught (UT2004)
For example:
BR-MyMap DM-AnotherMap
Some mods introduce their own prefixes, such as RA- for Rocket Arena, JB- for Jailbreak and OSM- for OSM Adventure.
Note that setting this prefix doesn't tell the map itself what gametype it is, you need to set the Level properties for that!
The prefix should always be capitalised or there will be problems with mapvote and linux based download redirect servers. Mapvote capitalises the prefix as part of its prefix changing logic, the UT server will find the file with lower case prefix because of its case insensitive match but the web server will not. Depending on server settings this will result in either a stream download (slow) or a refused to send error.