BIOS settings vary among hardware vendors and host models. A `FirmwareSchema` resource is a read-only resource that contains the types and limits for each BIOS setting on each host model. The data comes directly from the BMC through Ironic. The `FirmwareSchema` enables you to identify valid values you can specify in the `spec` field of the `HostFirmwareSettings` resource. The `FirmwareSchema` resource has a unique identifier derived from its settings and limits. Identical host models use the same `FirmwareSchema` identifier. It is likely that multiple instances of `HostFirmwareSettings` use the same `FirmwareSchema`.