Docker daemon writing to syslog but why

I’m running a docker CE setup and according to docker info the active logger is json-file. Nevertheless, my syslog is getting spammed with logs about NetworDB

Aug 21 23:45:17 myhost dockerd[859]: time="2019-08-21T23:45:17.488796292+02:00" level=info msg="NetworkDB stats myhost(68894b27f787) - netID:tm84fou4w4x98tgpqv19femay leaving:false netPeers:1 entries:6 Queue qLen:0 netMsg/s:0"

where is this message coming from? How can i configure it / disable it?

Source: StackOverflow