This site describes solve-engine as it is on main: 2.43.0, which npm does not have yet. npm installs 2.40.0, so a page may show an answer that version does not give yet.
UNCATEGORIZED_TOKEN_TYPES
const UNCATEGORIZED_TOKEN_TYPES: ReadonlySet<string>;Defined in: packages/engine/src/language/TokenCategoryMap.ts:380
Token types intentionally left uncategorized, either purely structural (never meant to be visibly styled) or already filtered out upstream before reaching a category lookup. Used only by the completeness test to distinguish “deliberately unstyled” from “forgotten.”