Device tree node names are communicated to the kernel from the boot firmware, so these are not defined inside the kernel source.
The pattern containing the
@ sign is typical for OpenFirmware. Unless your machine boots from OF, it is unlikely that you have any device tree nodes that match here.
The device-tree code still exists on ACPI based systems, as it allows attaching properties to ACPI device nodes, this is used mostly in embedded systems though (e.g. I have an embedded PC here that uses such a property to disable OTG mode and superspeed in the USB device controller).