My previous request was deleted even though I self-reported a follow-up post for deletion. Ah well.
Negate appliances are pfSense firewalls but the SysDecr flags as FreeBSD:
FreeBSD fw-01.example 11.3-STABLE FreeBSD 11.3-STABLE #233 2c992b2181a(factory-RELENG_2_4_5): Tue Mar 24 15:26:54 EDT 2020 [email protected]:/build/factory-crossbuild-245-amd64/obj/amd64/kkVaWThR/build/factory-crossbuild-2
The “netgate.com” string may be enough to identify it? Happy to query it for any extra information if you need.
Cheers.