Sites using public-key-pins-report-only:
3,460 proton.me
11,637 protonmail.ch
15,085 protonmail.com
26,584 protonvpn.ch
83,993 appointy.com
219,819 hackthissite.org
225,631 alliant.com
325,122 peterjin.org
332,395 proton.ch
458,510 hijup.com
701,084 intellicureehr.com
725,569 protonmail.fr
994,742 suravenir.fr