

Those people could be Polish or Ukrainian or born somewhere completely different
They have russian state-specific latin names transliterations Except for Roman Tsisyk, there’s nothing specific in name.
But most probably the guy from moscow got caught with russian ip which busted the whole gh organization. I don’t think gh has any other sanctioned regions users id methods
They can be de jure in Estonia and de facto wherever they want.
E.g OnlyOffice claim to be based in baltics too, but the development office is still in Nizhniy Novgorod(russia).