This one from 2015-06-02 10:15.

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What do you see if you go to Help / Manage Add-ons? I see only one, the bleeding build.

I see only one, but don't know which one it is. (Nor do I know how to tell, unless I decipher the version #, which in this case is "2.8.2".)

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I think the Preferences page just lists all updateSite.oxygen files that are known to Oxygen, not those which are active.

Your post nicely copies my original post to the list, though, which I was supposed to re-send, so I'll consider it re-sent.