The Windows WebHID authorization window shows "Unknown device (04A5:5801)" — is that my mouse?

The Windows WebHID authorization window shows "Unknown device (04A5:5801)" — is that my mouse?

Yes, this is normal — you can safely click to authorize.
When connecting via Bluetooth on Windows, the authorization window sometimes can't read the mouse's full model name in time, so it shows as "Unknown device."
Just confirm the ID is 04A5:5801 and click authorize; once connected, the web page will automatically display the correct model name.