nostr:npub12f7r2gjj0ch84wdh5kg03gkmjyskya6zlxq70cxlk5qm5sysjhuq08lkxh If you're talking about media cache, that's a Mastodon thing. It ensures media is in a playable format, has consistent thumbnails and metadata for previews, and protects users from 3rd party IP exposure and remote servers from hotlinking traffic. You can set it to only keep a certain amount of days worth of cache in settings.