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 *
For small rects there was a disagreement between two parts of the
layout algorithm. There is a function that decides if there is
enough space in a rectangle for a label. But this function was
called on two slightly different rectangles.
