We know that Apple says the iPhone's battery is essentially non-removable but one thing about technology. You say a tech feature of yours is "non" whatever, and someone will try to get around that.
Now I am going to save you some squinting.
As you can see in the screencap below, this "iPhone replacement battery" comes with the usual lawyered warnings:
"Please observe all static-safe precautions while working inside of your iPhone. We take no responsibility for damage occurring to your iPhone when installing this replacement battery. If you are concerned or are unable to perform this installation process, please contact a sales representative for a quote on professional installation service."