http://www.w5j6stm77zs6652pgsij4awcjeel3eco7kvipheu6mtr623eyyehj4yd.onion/w/index.php?title=Trust&action=edit§ion=13
Infrastructure in this context refers to "...hosting providers, CDNs, DNS services, package repositories, email servers, PGP keyservers, etc."
Third parties who operate infrastructure are "known unknowns" and potentially hostile. It is safer to voluntarily place trust in a few select entities, such as the contributors of {{project_name_short}} packages, the holder(s) of {{project_name_short}} signing keys and so on.