SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This allows converting a single virtual buffer into its non-physically
contiguous parts, this is especially useful for DMA-based devices that
support scatter/gather-like functionality, as it eliminates the need
to clone outgoing buffers into one physically contiguous buffer.