Is there a way in Linux-based operating systems to determine the source of text copied to the X clipboard?

Quick background info: I'm starting to build some software that will run within Gnome- and X-based operating systems to manage clipboard contents. One of the main functions will be to record the source URL of the copied text, if the copied text comes from a browser. I know this is possible on Windows (the Clipmate app开发者_StackOverflow中文版lication does this), but I want to do this within Gnome/X.

I have a sneaking suspicion that this might not be possible, because there's no software on Gnu/Linux that comes close to matching the functionality of Clipmate. Any guidance would be greatly appreciated though.

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Intercept and decode the SetSelectionOwner X message.