There are two layers of events, ''internal'' ones used by JBrowse plugins and components to communicate among themselves, and ''external'' ones used by other software to communicate with JBrowse.
external <-> controller <-> views
/jbrowse/v1/cmd/*
/jbrowse/v1/notify/*
Internal events are named for where they originate.
/jbrowse/v1/v: messages from views, mostly notifying other components
of what logical commands the user is issuing through her actions with
the view.
/jbrowse/v1/c: messages from controllers, such as requests to turn
on certain tracks, highlight certain features, and so forth.