Hi
@Jester
To answer your question, these are 25 digit license keys/product keys used to activate Windows 10 Pro.
You use the key to activate Windows and retain the key to prove you have purchased the right to do so, as per the link you provided.
Windows 10 can be installed without being activated, it can be cracked or as per the keys I resell, you use a licence/product key to activate Windows 10 Pro legally.
I trust that makes sense, let me know if you require any additional info or send me a PM
Sent from my HUAWEI VNS-L31 using Tapatalk