I am following the docs on how to provide, then inject a non-class instance; specifically I want to provide application wide constants. The docs use the InjectionToken for this, but the explanations are very bare; consider the first part:
app.config.ts
import { InjectionToken } from '@angular/core';
export let APP_CONFIG = new InjectionToken<AppConfig>('app.config');
What's the point of the 'app.config' string? Every example of InjectorToken that I see here uses that, but none discusses what it means or refers to.