Hi Micheal - sorry it took so long to respond. The plugin is way outdated - I haven't touched it in some time. I don't have any documentation on it and at last check, it didn't work with the latest few generations of Sage. If you still want it, I can email it to you (1.5 MB or so in size), but I am not sure if it will be useful to you. Send me an email at email@example.com and I'll respond with the file!
I noticed that some time ago you created GermSage plugin for enabling external players in SageTV. Since the link to the plugin is broken, would you mind publishing it again or sending it directly (I will provide an e-mail address).