The source is apparently, "Some Czech guy".

At least they plainly state at the beginning of the article: "Note: Some readers have commented that the original source for the article is of questionably validity. If anyone can confirm or refute the original author's finding with actual data, please let me know in the comments, and I'll update this post accordingly."

It would be good to see something confirming any of this. Even if all of this article's claims are false, it would be good to see a deep dive into exactly what is actually being sent and when.