The koto.zip file you have requested: Maps Levels Missions / 1 vs 1 / K to L Titles / Keep of the Overseer - 388.48kb is not available. Perhaps try browsing all files for the game Quake III Arena and upload any files you want to share or are missing. This is the only information we could locate:
Keep of the Overseer
Date : 4th Feb 2000
Editor: Q3Radiant build 181
Q3 arena addon level.
Put the rich2.pk3 file into your quake3aseq3 directory. A spacious 1v1 Tournament map,though you can play it ffa with about 3 bots if you're mad:)