Who makes Stihl chains?

Could you please clarify for me who exactly manufactures the Stihl chains that are commonly used in conjunction with their chainsaws? I understand that Stihl is a well-known and respected brand in the power tool industry, but I'm particularly curious about the origins and production of their chains. Are they produced in-house at Stihl facilities, or are they sourced from another manufacturer? Additionally, if they are sourced from another company, do you know which one specifically? I'm interested in understanding the supply chain and quality control measures involved in the production of these critical components.