The options a style records in its metadata, or undefined if it carries none — which is the case for
any style not written with styleMetadata, including every foreign style. Reconstructing options
from one of those is what @versatiles/style/migrate is for.
Never throws: anything malformed reads as undefined.
Recording the options a style was built from, and reading them back. Opt-in: the builders do not write this themselves — see the note on
styleMetadata. Free functions, so a bundle that never calls them drops them.