The Blender market link is not working right now because it’s pending approval. Till then if you would like to support me with any donation you can use the gumroad link.
Loving the addon so far! I did however come across a small bug. If you have the addon enabled and are in face mode, you can no longer double click a face to select a poly ring. If you do, you will get the following error: Active element must be an edge!
As mentioned on the product page the addon only works when selection mode is set to Edge so if you are in face or vertex select mode you will get that error message.
If you have some other operation assigned to double click in face mode than i can pass the event through so it can be handled.
I will add it in the next update.
Also I posted an addon that you requested some time back in the Free Script Series thread. So do check that out.