The class method was introduced in r12012 along with the instance method @CustomField#visibility_by_project_condition@. The method's body seems to follow the idea of the instance method but misses a lot of data required by it, including the @user@ and the @project_key@. As such, the method would always throw an exception when called.

Since the method is not tested, is never called by Redmine anywhere, and is unusable anyway, we can simply remove it as done by the attached patch.