If its a dns based control, one can dnswalk/iterate over the censored dns ipv4 space for example 1.1.1.1, then lookup the same ip in a public dns server such as opendns or google dns. By comparing the dns results from the censored and public dns you get the list of what censorship authority was trying to block. You can then publish the list of the address on for example Pastebin :)
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If its a dns based control, one can dnswalk/iterate over the censored dns ipv4 space for example 1.1.1.1, then lookup the same ip in a public dns server such as opendns or google dns. By comparing the dns results from the censored and public dns you get the list of what censorship authority was trying to block. You can then publish the list of the address on for example Pastebin :)