There is no official "2021 download" for this file as it is standard across most Android versions. If your device supports USB Host hardware but lacks the configuration, you can manually create it or download it from developer repositories:
The system uses this file to advertise that the device can act as a USB host, allowing it to detect and communicate with connected USB peripherals such as flash drives, keyboards, mice, game controllers, and even specialized hardware like USB-to-serial adapters. Without this file present, the PackageManager won't know that USB host capabilities are available, and the UsbHostManager service will not start. androidhardwareusbhostxml file download 2021
Android.hardware.usb.host.xml File Download 2021: Enabling USB Host Mode There is no official "2021 download" for this