Most popular variants of the header value (we only show this when there's just a bunch of variants):

Announces a list of X.509 certificate hashes that are allowed to appear in the website's TLS certification path (HTTP Public Key Pinning or HPKP). This prevents malicious proxy servers from transparently replacing the public certificates with their own and wiretapping the TLS connection of the unsuspecting user. This header sets HPKP in report-only mode.

Reference...

We have seen 34 websites setting the Public-Key-Pins-Report-Only HTTP header and 24 unique values of this header.

  • protonmail.com pin-sha256="8joiNBdqaYiQpKskgtkJsqRxF7zN0C0aqfi8DacknnI="; pin-sha256="drtmcR2kFkM8qJClsuWgUzxgBkePfRCkRpqUesyDmeE="; report-uri="https://reports.protonmail.ch/reports/tls"
  • mail.protonmail.com pin-sha256="8joiNBdqaYiQpKskgtkJsqRxF7zN0C0aqfi8DacknnI="; pin-sha256="drtmcR2kFkM8qJClsuWgUzxgBkePfRCkRpqUesyDmeE="; report-uri="https://reports.protonmail.ch/reports/tls"
  • service.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/nullm";
  • org62.my.salesforce.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00D000000000062m";
  • op1static.oktacdn.com pin-sha256="jZomPEBSDXoipA9un78hKRIeN/+U4ZteRaiX8YpWfqc="; pin-sha256="axSbM6RQ+19oXxudaOTdwXJbSr6f7AahxbDHFy3p8s8="; pin-sha256="SE4qe2vdD9tAegPwO79rMnZyhHvqj3i5g1c2HkyGUNE="; pin-sha256="ylP0lMLMvBaiHn0ihLxHjzvlPVQNoyQ+rMiaj0da/Pw="; max-age=60; report-uri="https://okta.report-uri.io/r/default/hpkp/reportOnly"
  • www.hackthissite.org pin-sha256="YLh1dUR9y6Kja30RrAn7JKnbQG/uEtLMkBgFF2Fuihg="; pin-sha256="Vjs8r4z+80wjNcr1YKepWQboSIRi63WsWXhIMN+eWys="; max-age=2592000; includeSubDomains; report-uri="https://hackthissite.report-uri.com/r/d/hpkp/reportOnly"
  • ok1static.oktacdn.com pin-sha256="r5EfzZxQVvQpKo3AgYRaT7X2bDO/kj3ACwmxfdT2zt8="; pin-sha256="MaqlcUgk2mvY/RFSGeSwBRkI+rZ6/dxe/DuQfBT/vnQ="; pin-sha256="72G5IEvDEWn+EThf3qjR7/bQSWaS2ZSLqolhnO6iyJI="; pin-sha256="rrV6CLCCvqnk89gWibYT0JO6fNQ8cCit7GGoiVTjCOg="; max-age=60; report-uri="https://okta.report-uri.com/r/default/hpkp/reportOnly"
  • c.eu6.content.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/nullm";
  • brokeriq-8c29.kxcdn.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/nullm";
  • c.um3.content.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/nullm";
  • landing.traffstock.net pin-sha256="stKntoSy6rH12AR30z5+hClgM7F3cOSPzoaMIdv/UIw="; pin-sha256="wzWjiEHSbUkf3z+DKlYfid+5Gdr9NIyQHgPa3mYu/qs="; max-age=31536000; includeSubDomains; report-uri="https://traffstock.net/?mod=ticket_system&do=ticket_create"
  • ok7static.oktacdn.com pin-sha256="r5EfzZxQVvQpKo3AgYRaT7X2bDO/kj3ACwmxfdT2zt8="; pin-sha256="MaqlcUgk2mvY/RFSGeSwBRkI+rZ6/dxe/DuQfBT/vnQ="; pin-sha256="72G5IEvDEWn+EThf3qjR7/bQSWaS2ZSLqolhnO6iyJI="; pin-sha256="rrV6CLCCvqnk89gWibYT0JO6fNQ8cCit7GGoiVTjCOg="; max-age=60; report-uri="https://okta.report-uri.io/r/default/hpkp/reportOnly"
  • fluke667.host pin-sha256="W58VU4UqbLvxCT+fQvcvrvnzBxflAVdZfUh9XlyXdF4="; pin-sha256="r+zpFN7FC0Prp7i+E7qZrUpw5sy9sYSyR3m1eAxZoyE="; max-age=5184000; includeSubDomains
  • escardio--community.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00DD0000000ojxtm";
  • isoftbet.my.salesforce.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00D0Y000002Gjbtm";
  • amersportssurveys.secure.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00Db0000000ILKFm";
  • vulnerability-developer-edition.um1.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00D3z000001hirWm";
  • ok11static.oktacdn.com pin-sha256="r5EfzZxQVvQpKo3AgYRaT7X2bDO/kj3ACwmxfdT2zt8="; pin-sha256="MaqlcUgk2mvY/RFSGeSwBRkI+rZ6/dxe/DuQfBT/vnQ="; pin-sha256="72G5IEvDEWn+EThf3qjR7/bQSWaS2ZSLqolhnO6iyJI="; pin-sha256="rrV6CLCCvqnk89gWibYT0JO6fNQ8cCit7GGoiVTjCOg="; max-age=60; report-uri="https://okta.report-uri.com/r/default/hpkp/reportOnly"
  • connect.bolt.com max-age=2592000;pin-sha256="OGAVOYhLZd3ADKYGFZOED1c5m1ObMlRv9PyIWrO4Nd0=";pin-sha256="RRM1dGqnDFsCJXBTHky16vi1obOlCgFFn/yOhI/y+ho=";pin-sha256="IXHYSIdST+XY22J5ivybYkntMIfjA5P6pMKX2hWG1BE=";report-uri="https://77aa1bd121ef22d50247a23390ce6cff.report-uri.io/r/default/hpkp/reportOnly"
  • grupoexito.my.salesforce.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00D1U000000t4Onm";
  • api.bolt.com max-age=2592000;pin-sha256="OGAVOYhLZd3ADKYGFZOED1c5m1ObMlRv9PyIWrO4Nd0=";pin-sha256="RRM1dGqnDFsCJXBTHky16vi1obOlCgFFn/yOhI/y+ho=";pin-sha256="IXHYSIdST+XY22J5ivybYkntMIfjA5P6pMKX2hWG1BE=";report-uri="https://77aa1bd121ef22d50247a23390ce6cff.report-uri.io/r/default/hpkp/reportOnly"
  • rbx.okta.com pin-sha256="r5EfzZxQVvQpKo3AgYRaT7X2bDO/kj3ACwmxfdT2zt8="; pin-sha256="MaqlcUgk2mvY/RFSGeSwBRkI+rZ6/dxe/DuQfBT/vnQ="; pin-sha256="72G5IEvDEWn+EThf3qjR7/bQSWaS2ZSLqolhnO6iyJI="; pin-sha256="rrV6CLCCvqnk89gWibYT0JO6fNQ8cCit7GGoiVTjCOg="; max-age=60; report-uri="https://okta.report-uri.com/r/default/hpkp/reportOnly"
  • ciscocert-learningatcisco.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00DA0000000YXoLm";
  • na58.salesforce.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/nullm";
  • amli-uk-leaseplan.cs81.force.com pin-sha256="9n0izTnSRF+W4W4JTq51avSXkWhQB8duS2bxVLfzXsY="; pin-sha256="5kJvNEMw0KjrCAu7eXY5HZdvyCS13BbA0VJG1RSP91w="; pin-sha256="njN4rRG+22dNXAi+yb8e3UMypgzPUPHlv4+foULwl1g="; max-age=86400; includeSubDomains; report-uri="https://a.forcesslreports.com/hpkp-report/00D26000000E9n1m";