What is the principle by which the list of incorrect addresses is compiled in Yandex.Post Office?

Question

Yandex

In the Yandex Post Office ( postoffice.yandex.ru ) there is a “Delete these addresses” block on the right. In my case, there are about five thousand such addresses, and I don’t feel like throwing them out of the mailing without understanding.
Since there are no explanations, it is not clear whether these are (already?) non-existent addresses, or those that do not accept letters (run out of space?), Or simply those on which letters end up in spam.
Thanks for any information, even if you throw a link to the mana. I didn't find anything in the help.