I read the article (no fair!)
> The new Advanced Wireless Receiver (which is built into the power cord) needs to be used with the Roku Streaming Stick+. The mini-USB port will help users not substitute another cable.
I have one of these cords, from a cheap mini speaker / USB mp3 player.
They should be able to recommend some if it is a requirement. Almost all have an interface.
https://www.amazon.com/Haoponer-Portable-Digital-Display-Speaker/dp/B010AUWVLK
https://www.amazon.com/Haoponer-Portable-Digital-Display-Speaker/dp/B010AUWVLK
To rephrase your question, you have a USB that contains .MP3 or .WAV files and you want to plug it into something that can read those files individually, and then convert the files into sound. You want to retrofit this into your Sony clock radio.
There are small devices such as this: https://www.amazon.com/Haoponer-Portable-Digital-Display-Speaker/dp/B010AUWVLK
It's conceivable that you could take out the main board and connect the power from and sound output to your clock radio.
However, I don't know how much unused space is in your clock radio. Also you would probably need to retain access to the device's buttons to make the USB play and skip between files.