How does Yandex.Food determine the service user account when going to their Telegram bot?

Question

Yandex

Friends, I recently encountered a surprising thing for me: I go to the Yandex.Food application, then from the "Contact Us" section I go (after clicking on the appropriate icon) to their Telegram bot with a live operator. I do not provide any information about myself, but the operator sees that I did not come from the street, but my name, phone number - everything that is indicated in the Yandex.Food account. This fact puzzled me a lot - how does Yandex do this? I would understand if the bot had a unique name that is generated every time for a new user - then there would be no questions, but no, the name is standard for everyone ... Topic gurus, tell me how is this possible?

Answer 1

If you create a link correctly, then linking an account at the start of the bot is not a problem. Link to doc

Answer 2

Apparently in your telegram everyone is allowed to see the phone number.
The operator asked me for a number, because. in the settings should be shown only to contacts.