| Subdomain | First seen | Last seen | DNS | Certificate issuer | Report |
|---|
| openpgpkey.mailman.dev | Jan 2023 | Oct 2026 | Resolves | Google Trust Services | Report → |
| www.mailman.dev | Jan 2023 | Feb 2025 | Resolves | Google Trust Services | Report → |
| app.mailman.dev | Mar 2021 | Sept 2021 | No DNS | Let's Encrypt | Report → |
Found in public certificate transparency logs, which record every publicly trusted certificate. Some subdomains may no longer exist.