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Minor spoiler.

I picked up the game again after a break, re-read the manual and replayed a few challenges. As part of the story, in one of the in-game emails they mention that the undocumented gen command and the @ symbol were left out of the English manual due to poor translation and they can be found in the original Chinese documentation.

Now that there is Chinese localisation for the game, can those commands be found in the actual Chinese manual or they explain their absence in a different way? :)