I have set myself a noble goal of making sure that packagekit works well for end users. In order to make finding and debugging packagekit issues easier, I want to run packagekitd with --verbose option by default. However, I fail to find out how to do that.

When I look into /etc/PackageKit/PackageKit.conf, there's no option for increased verbosity.

In the Reporting Bugs and FAQ sections on the web, there's no info either:
http://www.freedesktop.org/software/PackageKit/pk-bugs.html
http://www.freedesktop.org/software/PackageKit/pk-faq.html

If I override the existing systemd unit file in /etc and add --verbose as a default argument, packagekit doesn't start at all (I have no idea why):

$ sudo systemctl stop packagekit.service
$ sudo cp /usr/lib/systemd/system/packagekit.service /etc/systemd/system
$ sudo vim /etc/systemd/system/packagekit.service  # add --verbose
$ sudo systemctl daemon-reload 
$ systemctl cat packagekit.service 
# /etc/systemd/system/packagekit.service
[Unit]
Description=PackageKit Daemon

[Service]
Type=dbus
BusName=org.freedesktop.PackageKit
User=root
ExecStart=/usr/libexec/packagekitd --verbose
$ pgrep -fl packagekit
$ sudo systemctl start packagekit.service
Job for packagekit.service failed. See "systemctl status packagekit.service" and "journalctl -xe" for details.
$ systemctl status packagekit.service 
● packagekit.service - PackageKit Daemon
   Loaded: loaded (/etc/systemd/system/packagekit.service; static)
   Active: failed (Result: timeout) since Sat 2015-04-04 09:41:27 CEST; 2min 8s ago
  Process: 28148 ExecStart=/usr/libexec/packagekitd --verbose (code=killed, signal=TERM)
 Main PID: 28148 (code=killed, signal=TERM)

Apr 04 09:39:57 medusa packagekitd[28148]: 09:39:57        PackageKit        Verbose debugging enabled (on console 0)
Apr 04 09:39:57 medusa PackageKit[28148]: daemon start
Apr 04 09:41:27 medusa systemd[1]: packagekit.service start operation timed out. Terminating.
Apr 04 09:41:27 medusa systemd[1]: Failed to start PackageKit Daemon.
Apr 04 09:41:27 medusa systemd[1]: Unit packagekit.service entered failed state.
Apr 04 09:41:27 medusa systemd[1]: packagekit.service failed.


If I don't include --verbose on the ExecStart line, everything works correctly.

Is this a bug or intention? Can you help me run with --verbose by default?