Declared as a runtime list first, like EPUB_VERSIONS above, so callers that
must validate user input have something to check against. Left as a bare
union, every such caller hand-copied the members: the CLI and the parity
harness each grew their own list, and a profile added here would have been
silently rejected by both.
EPUB validation profiles
Declared as a runtime list first, like EPUB_VERSIONS above, so callers that must validate user input have something to check against. Left as a bare union, every such caller hand-copied the members: the CLI and the parity harness each grew their own list, and a profile added here would have been silently rejected by both.