http://magma.ua4vjlx72wv5crhkificaeysp62hizhazipfshsdvs6jxqvhtkpllcad.onion/guide/network-measurements.html
Although VPNs provide
access to different vantage point locations, the VPNs themselves are usually not
subject to information controls or other network blocking restrictions (note,
however, that the real locations of various VPNs are not always marketed
accurately). Further reading: Razaghpanah, Abbas & Li, Anke & Filastò, Arturo & Nithyanand, Rishab &
Ververis, Vasilis & Scott, Will & Gill, Phillipa. (2016). Exploring the Design
Space of Longitudinal Censorship Measurement Platforms.