I'm taking over the excellent facebook-extended.txt hosts list after his repo is archived.

• In case you find a domain that is not listed in the manual-domains file

You can add it to this file, which is sorted alphabetically. I'd search for valid sub-domains.

Command to sort the file:

sort -u FILE -o manual-domains

• If you find a valid sub-domain that is not blocked

You can create the manual-subdomains file, if not already present and add it to this new file (format: xyz.example.com). It will be sorted alphabetically too.

• Otherwise, if you're not familiar with git , you can also open an ISSUE

Thank you @lightswitch05 for your work.