There have been only two photo editors that fully support the PSD format: Photopea and Adobe Photoshop. When a new one appears, which fully supports the PSD format, from an anonymous creator, it is very likely a copy one of these two. And they usually name it Photopea-offline, etc.
but does it actually fully support the PSD format or is it false advertising?
This day in age, we need to verify ourselves
Can you show us an example? How did you verify?