Files in this directory specify a description of hardware devices, in the form of mappings from modalias-like keys (which identify specific hardware devices) to udev properties. Files in this directory are not read by udev directly. Instead, man:systemd-hwdb(8) compiles them into a binary database. See man:hwdb(7) for an overview of the configuration file format, and man:systemd-udevd.service(8) for a description of the udev daemon. Use 'systemd-analyze cat-config udev/hwdb.d' to display the effective config.