These days there are better ways to collect traces from connman.
Enabling traces at startup involves some additional command line action
anyway (e.g. lifting journald limits so that messages don't get dropped)
and with that in mind, installing a package just to add -d to the command
line makes very little sense. A person capable of collecting connman traces
at startup should be able to directly edit the connman.service file. And
it's probably easier for such a person to edit the file than to install