Skype at one point was somewhat decentralized, but now the main hubs are located on Microsoft's servers to my understanding. urls included in Skype chats have

Skype at one point was somewhat decentralized, but now the main hubs are located on Microsoft's servers to my understanding. urls included in Skype chats have been known to be visited by bots at Microsoft owned IPs so no end to end encryption of urls at the very least. If I remember correctly Microsofts reasoning is that the bots at Microsoft check to make sure the links are not infected with malware. That are the two pieces of evidence that I see brought up when people have conversations on the topic.