Heroku config vars provide application configuration through the runtime environment. The original note showed the CLI form heroku config:set NAME=value and the dashboard’s Settings → Config Vars controls.
Use the intended application’s context when changing a value. A successful command updates configuration; it does not prove that the application has interpreted that configuration correctly.
The old note linked a particular application’s dashboard. That environment-specific link and its token example are omitted here. Real secrets should not appear in a shared command transcript or screenshot.
See Heroku’s config-var documentation for the platform’s current behavior. No hosted application was changed for this revision.