Cache file saved by Runescape, an online multiplayer game; stores game progress on a player's local machine; used when resuming a game online; typically named "main_file_cache.idx255" and is saved with several other cache files.
Program(s) that open idx255 files
Windows: Jagex Runescape
Information from FileInfo.com - The File Extensions Resource.
http://www.fileinfo.com/extension/idx255
