This is repo contains the source for the c/pubsub component that was made available when Lightning Web Components (LWC) were launched in early 2019. This component was a temporary solution for lack of feature-parity between LWC and Aura components related to cross-DOM messaging.
The Aura components <aura:event> feature allowed for messaging between components across a complex DOM tree structure.
c/pubsub served to implement an analogous feature that would work for LWC and Aura components.
As of July 2020, c/pubsub has been superseded by the Lightning Message Service. For this reason it has been retired from our sample apps.
However, as there are still some limitations with Lightning Message Service, we've kept the core components involved in using c/pubsub available in this repo for use by Salesforce developers.
Please remember that c/pubsub falls under no support agreement with Salesforce.