As a player, I would like to be able to find servers which are running a specific plugin.  As a plugin author, I'd like to find servers which are running my plugin to see how players are using it and maybe even get some feedback.  Wouldnt it make sense then to have a configurable feature in oxide which allows it to register the server running this plugin to a "Umod server browser" service.  Or it can even be a manual process where admins or even other players can provide this information and its shown on the plugin page.  This way players can filter by plugins/version and find a server which more accurately meets their needs.  Does this already exist?

There isn't a way to really know that without installing something on the server. We have plans for uMod to provide that sort of anonymous details for plugins on our site, but that isn't available at the moment.

I was curious so I just tested it. You can have a plugin which can scan for other plugins and sends a request on server init.  You just need a one liner.  Although you'd probably want to make it a post request and add server details and port and all that.  But my test worked just fine with this:

UnityWebRequest.Get("https://foo.com/myplugin/1.3").SendWebRequest();

Then at the service level you just keep track of these incoming requests.  Maybe you can have them expire after a while due to inactivity if no new updates come through.  

But yeah, its cool that you're working on something like this!  I think it would be very useful!

Yes, doing it in a plugin would work, but generally not encouraged for plugins to randomly send info from the server. Using the web request library from Oxide would be the encouraged way for any web requests though, not Unity.

The information they uMod would provide would generally be opt-in for privacy, with no identifying information.

Yes of course, this would have to be something well made which isn't spamming requests all the time.  But one request a day or on server init or something like that (if you don't wait for a response) should have very little impact on the sever performance.  Then you can have the admin configure the plugin's config with whatever data they want to send for the privacy concerns.  I think it would be pretty simple to do actually.  It's also 100% opt in because it will only work if you manually download and install the plugin.