Jmail is a mix of sources.

“The Jmail Suite is an interactive archive of Jeffrey Epstein's emails, documents, photos, and more. Data compiled from the House Oversight Committee, Department of Justice, and DDoSecrets releases”

If I understand correctly, the emails you’re looking at are from a leak that is only accessible to journalists — so Drop Site News (as journalists) have access and have published some.

https://ddosecrets.org/article/epstein-emails