Stable for the life of the tab, surviving reloads and reconnects.
Not a security token and not globally unique — it exists to disambiguate a handful of connections in a picker, nothing more.
OptionallabelOperator-supplied name from ?session=, e.g. left-monitor.
The only part of this a human chooses, and the only part that can say something a machine cannot infer.
OptionalviewportViewport at the time of the identify, e.g. 1920x1080.
Distinguishes a full-screen alert source from a slim progress bar without
anyone having to type anything, which makes it the useful half for
streamers, who will never set ?session=.
Identity of the tab a pipeline connection is running in.