I have downloaded the Eagle CAD documentation files for a couple of the Arduino boards (MKR ENV Shield for example), because it seemed like a reasonable place to start with a custom shield design. Those designs all seem to reference a number of "Arduino-???" Eagle CAD libraries; for example, "Arduino-utility", "Arduino-rcl" and "Arduino-connectors". I have done my best to locate those libraries, but have not had any luck. Are those libraries available for download somewhere? It would be very helpful to have them.
You can export Libraries from the board you have open.
Thank you so much! I've used a couple of other professional schematic/layout tools, but for some reason Eagle has not been intuitive for me.