Mail::ListDetector::Detector::Smartlist(3pm) on Linux
The text 00e4b1aca0e6, as Debian 11 (Bullseye), Debian 10 (Buster) shipped it.
Smartlist message detector
The text 00e4b1aca0e6, as Debian 11 (Bullseye), Debian 10 (Buster) shipped it.
Smartlist message detector