src/vs/editor/common/tokens/contiguousTokensStore.ts/getDefaultMetadata
function getDefaultMetadata(topLevelLanguageId: LanguageId): number {
	return (
		(topLevelLanguageId << MetadataConsts.LANGUAGEID_OFFSET)
		| (StandardTokenType.Other << MetadataConsts.TOKEN_TYPE_OFFSET)
		| (FontStyle.None << MetadataConsts.FONT_STYLE_OFFSET)
		| (ColorId.DefaultForeground << MetadataConsts.FOREGROUND_OFFSET)
		| (ColorId.DefaultBackground << MetadataConsts.BACKGROUND_OFFSET)
		// If there is no grammar, we just take a guess and try to match brackets.
		| (MetadataConsts.BALANCED_BRACKETS_MASK)
	) >>> 0;
}