Apple Cinema Display support for HDCP

[High-bandwidth Digital Content Protection](https://en.wikipedia.org/wiki/High-bandwidth_Digital_Content_Protection) (HDCP) was released in the mid-2000s, contemporaneous with the Apple Cinema Display line of external monitors: - 23", 30" Apple Cinema Display - 24", 27" Apple LED Cinema Display - Apple Thunderbolt Display Did any of the above monitors support HDCP? Can a connected macOS system display be queried to determine if it supports HDCP? This is relevant as many of the adapters needed to connect these monitors to a modern USB-C / Thunderbolt Mac have "HDCP on" and "HDCP off" versions of the same adapter. Which should be used? How can you determine if an Apple external monitor supports HDCP?