Service quotes about #HSTS/#HPKP from http://blog.en.elevenpaths.com/2017/12/breaking-out-hsts-and-hpkp-on-firefox.html…

Firefox: size limit 1024 entries + website scoring
-> you can kick sites out of the list

Chrome/ium: unlimited JSON file
-> you can DDOS it by filling it >= 500MB

IE/Edge: completly broken
-> seems to store sth. but only applies HSTS to big websites

Test yourself: https://www.cloudpinning.com/