Oh, the only file the game can download is backup files (.json) when you press the world screen backup button or at settings > data > backup worlds.
If that file downloads, it means that when the cache of the browser resets, the game will lose ALL worlds and progress. (Of course, you can re-upload the backup (.json) file to back up the game.
To help you figure it out, I wanna know what file name/file extension.
See those photos for a better understanding of what I’m saying.
Backup and import options.
The file name should download.
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