The xk-protocol is a new extension to x-callback-url built by Ben Slotznick and Stephen Sheetz at Point-and-Read. xk-protocol builds on x-callback-url with additional parameters to specify named pasteboards, and to target multiple interaction types in other apps.

xk-protocol is informed by Ben and Stephen’s work with Assistive Technologies and looks like a great project, looking forward to seeing it in action!