SAN FRANCISCO — A panel of the U.S. Court of Appeals for the Ninth Circuit on Wednesday afternoon heard oral arguments in a case that challenges arbitration agreements between Uber Technologies Inc. and its drivers as violating the National Labor Relations Act.

Here is a primer on the various issues presented on appeal. Below are highlights from the hearing in front of Ninth Circuit Judges Sandra Ikuta, Richard Clifton and Richard Tallman, which was broadcast over the internet live.