[Bender]

Websites have public key pinning. [1] HPKP Most sites don't do this any more but enough do that anyone running a Squid SSL Bump MitM proxy needs to know.

[1] - https://en.wikipedia.org/wiki/HTTP_Public_Key_Pinning

[inigyou]

And do you block children from accessing any of them?

[Bender]

Which of them specifically are you asking about?