I realized that despite the fact that I give syncthing a logfile via its commandline it continues to log to stdout, leading to log entries being placed in my logfile as well as in daemon.log and syslog. How do I prevent that? Of course I want syncthing to log to one file only! Syncthing is started like so:
ExecStart=/usr/bin/syncthing -no-browser -logfile=/var/log/syncthing/syncthing.log -logflags=3
What else do I need to do to stop it from spamming syslog?