.IDX255 File Extension

Runescape Cache File

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.
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Created by the on-line multiplayer RPG 'Runescape', these .IDX255 files are cache files that are used by the game to save progress on a client's computer.

These files are then used when resuming an on-line session.

Often named 'main_file_cache.idx255'