What does HTTP-Based Public Key Pinning mean on Toaster?

Question

Web servers

A strange entry "Public-Key-Pins" was found in the headers of the toaster:

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Chrome throws an error:

HTTP-Based Public Key Pinning is deprecated. Chrome 69 and later
will ignore HPKP response headers. (Host: toster.ru)

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Answer 1

HTTP Public Key Pinning (HPKP) is a technology to reduce the risk of MITM attacks, read on MDN .