Suggestion to add more information on deviceID

Can I suggest to add a bit more information about how to specify the deviceID?

Because it is not very clear for the customer that the deviceID is used for identifying each user that connects to the application.
And needs to be used with only digits.

Based on a conversation on Slack:
_Custom applications have the same behavior then mobile applications: Not every session is tagged, especially when the user did not accept the privacy settings. Therefore the metric is based on the device id._

The official documentation is also not very clear: https://docs.dynatrace.com/docs/shortlink/user-session#user-session-identification

My customer has implemented it by specifying the ID of the application and not the ID of the users so in consequence, only 1 unique user was reported:

Thank you!

Beginne mit der Durchsicht der Beispiele im Issue und der verlinkten Dynatrace-Dokumentation zu user-session. Aktualisiere die relevanten Hinweise zu deviceID, sodass ihr Zweck zur Benutzeridentifikation, die Anforderung, dass sie nur aus Ziffern bestehen darf, und die Abgrenzung zu einer application ID eindeutig sind; überprüfe, dass die Dokumentation erklärt, warum falsche Werte die Metriken für eindeutige Benutzer beeinflussen.

Vom Indexierungsmodell aus dem Issue-Text verfasst.