Threema publishes two privacy policies and both of them govern its website. Neither describes what the messenger does with your messages. That is a documented absence, n…
Paste this where the card should sit. It is the live verdict: if the grade changes, the card changes. It loads nothing from anywhere but this site and sets no cookie.
Editors that support oEmbed (WordPress, Ghost, Substack and most newsroom systems) can paste the entry's address instead, https://isittrainingonme.com/app/threema/, and get the same card.