There are two Plex-related channels available for Roku players: the regular Plex channel and a Plex Classic channel.
Related Page: Why are there both Plex and Plex Classic channels?
Our current Plex channel is custom, written from the ground up, and developed entirely by Plex. This app is not open source.
The Plex Classic channel was our original channel for Roku players and began with community developers. The existing roku-client-public project is open source and remains available on GitHub. It forms the basis for the (also free) Plex Classic channel. It is no longer officially supported by Plex.