ZIP: https://drive.google.com/file/d/1qE-fWY4uThDWFMM52edhgsw0VSi-5-PU/view?usp=sharing
Captcha is rendered on maps in minecraft originally, so it has only 255 possible colors (~220 maybe), and can be encoded in one channel. Size is 384x384. There is no access to the source code, so training data cannot be automatically generated (captcha can be generated, but the answer is unknown)