/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ATS.framework/ATS App Transport Security (ATS) improves privacy and data integrity for all apps and app extensions. It does this by requiring that network connections made by your app are secured by the Transport Layer Security (TLS) protocol using reliable certificates and ciphers. ATS blocks connections that don't meet minimum security requirements. Deprecated in OS X v10.8. Use CoreText.framework instead.
The binary is a part of ApplicationServices public framework.