OK, good then.
So the assumption (in the general absence of any other information) is that the current foreground application is responsible for the clipboard, but if you are a background app, or if you want to make it explicit, you can use the flavour:
org.nspasteboard.source
(spelled correctly, sigh ;-)
which contains a bundle ID which is the Application Bundle ID of the source of the clipboard as a string.
Potentially down the track there might be special case bundle IDs for things like universal clipboards, but where possible (and for ongoing backward compatibility) it should be an application bundle ID as users will likely display the associated application icon as the responsible party.
There would generally be no need for most applications to set this flavour as they typically only change the clipboard while they are the foreground application anyway, but there is no harm in setting it universally if desired.
Can someone add that to the
http://nspasteboard.org site?
I will start using it in a future version of Keyboard Maestro.
Once it is on the site as a spec, I will do a radar/openradar to ask Apple to support it, especially for universal clipboard, and post for duplication here.
Thanks,
Peter.