The [https://datatracker.ietf.org/doc/draft-kucherawy-dmarc-base/ DMARC draft RFC] uses the PSL to determine the "organizational domain". This is where the DMARC algorithm looks for DNS records relating to DMARC. (This usage should probably exclude the PRIVATE area, but the draft does not currently say that it should.)
===HTML5HTML===
As noted above, the HTML5 standard HTML Standard references the PSL when defining how the for document.domain property should be implementedand IsSearchProviderInstalled().
==Other==