What does 8.8 mean on a bolt?

Could you please clarify what context or industry the bolt and the number 8.8 are being referred to in? In general, the number 8.8 on a bolt could indicate its strength class or grade, which is a measure of its mechanical properties such as tensile strength and yield strength. However, without more specific context, it's difficult to give a definitive answer. Is this related to a particular standard or specification? Or perhaps it's a common notation in a specific industry or application?