In order to make the Public Suffix List as current and accurate as possible, we request that TLD registries put in place processes to keep their section of the list current and accurate. This will make sure that all sites within their TLD continue to function fully within modern browsers, in terms of the site owners' ability to set cookies and so on.
In addition, owners of privately-registered domains who themselves issue subdomains to mutually-untrusting parties may wish to be added to the PRIVATE section of the list.
The procedure to make changes is documented on our wiki.
Requests for changes to the PRIVATE section MUST come from the domain owner - we have this rule to make sure that domain owners are fully aware of the consequences of being added to the list. We will not make additions to this section if they are requested by third parties. Requests for changes to the ICANN section either need to come from the registry, or come with links to supporting official documentation.