_parseOptionsCached(library) {
		if (!library) return false;
		if (library.type !== this._type) return false;
		const cacheEntry = this._parseCache.get(library);
		if (cacheEntry !== undefined) return cacheEntry;
		const result = this.parseOptions(library);
		this._parseCache.set(library, result);
		return result;
	}
@param {LibraryOptions=} library normalized library option
@returns {T | false} preprocess as needed by overriding