Mail::ListDetector::Detector::RFC2919(3pm) on Linux
The text a990f7021b16, as Debian 11 (Bullseye), Debian 10 (Buster) shipped it.
RFC2919 message detector
The text a990f7021b16, as Debian 11 (Bullseye), Debian 10 (Buster) shipped it.
RFC2919 message detector