I recently purchased a 2021 Cadillac XT5 and have the three-month preview of SiriusXM on the car's radio. While playing with the controls, I noticed that I can actually go back in time and play songs that have already played. It appears to start "recording" from the time I start the vehicle. On a long car ride (30 minutes) it seemed like I could go back for at least seven or eight songs. But the bigger surprise is that this appears to work for channels that I have in my favorites but haven't been listening to. I can tune to another channel and skip backwards to see what I missed. This is totally unexpected and I'm wondering how it works. Is the radio "recording" the entire satellite data stream? If so, for how long? I've never seen this feature before and I have to say I really like it. It may cause me to subscribe again.