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Here's your proof ...

This is Maksim Bugrimov confirming these assets are his and not their creation.

Screenshot 2021-10-04 151003.png

... well the whole email seens "valid" with no source of email front him or even worse, if you claim he told you that by social media it would be insta redflagged because instagram and facebook were down today...

Email him yourself and ask if you like. His email address is publicly available on his profile page on Unity.

Ok i guess i will :D