I think opening a ticket with Support and asking them to ask the Spectrum Dev team, "can anything else be passed under com.aprisma.spectrum.app.util.context.ApplicationContext besides USER_PARAMETER_NAME?" will be your best bet.
I've wondered this for a few years, and grepping all the logs/configs/SDK docs comes up with nothing.
It would be great if they listed all the methods and variables accessible under com.aprisma.spectrum.app.util.context.DefaultApplicationContext.