Bonus Cheat panel (OBSERVED)

Location: icon beside the volume button, bottom-left of the game. Opening it made no API call (only cached static files were re-read).
Title "BONUS CHEAT". Options seen: None, a grid of 5H1 4H1 3H1 2H1 5H2 ... 3H5 (high symbols, 2 to 5 of a kind), 5L1 ... 3L5 (low symbols), 5 Scatter, 4 Scatter, 3 Scatter, 2 Scatter, Feature Miss, BIG WIN. (The middle of the list was visible only in two screenshots; exact full list not exported.)
Selecting an option closed the panel with no network call. It arms the next spin.
Effect on the wire: the next POST /spin carried an extra field combination (base64 string). For "3 Scatter" it was MTc1LDE3OCwxNzAsMTUwLDE2Nw==, which decodes to 175,178,170,150,167 (five numbers, probably one per reel, meaning unverified).
The same combination value was also sent on every POST /feature call of the resulting free-spin round.
Used once, with your approval. I did not try other options, edit the combination, or test whether the server accepts arbitrary values.
Caveat: forced outcomes bypass normal RNG. Do not treat them as realistic frequencies or timing.