Mail::SPF::Mech::IP4(3pm) on Linux
The text 4b55fb4d5c89, as Debian 12 (Bookworm), Debian 11 (Bullseye) shipped it.
SPF record "ip4" mechanism class
The text 4b55fb4d5c89, as Debian 12 (Bookworm), Debian 11 (Bullseye) shipped it.
SPF record "ip4" mechanism class