Privacy clarifications while checking `app_id`

[espinr]

Closes #55

This change (choose at least one, delete ones that don't apply):

• Makes editorial changes (changes informative sections, or changes normative sections without changing behavior)

If it changes the specification itself, the following tasks have been completed:

• [X] Confirmed there are no ReSpec errors.

Commit message:

Added clarification text about the possibility to verify integrity of the app to increase users' trust.

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