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 *
It's a little awkward that we do this in two places, but IPWV and OOPWV
currently implement resizing a little differently from each other so we
need to cover both paths.
