http://magma.ua4vjlx72wv5crhkificaeysp62hizhazipfshsdvs6jxqvhtkpllcad.onion/guide/testing-methodology.html
Important data such as
network errors, DNS settings, DNS entries, HTTP codes, and HTTP headers may be
collected to assist in determining the specific blocking method that is being
used. Further information about this type of testing methodology can be found
here: ONI Methodology, Tools, and Data FAQ .