extensions/html-language-features/server/src/customData.ts/parseHTMLData
function parseHTMLData(id: string, source: string): IHTMLDataProvider {
	let rawData: any;

	try {
		rawData = JSON.parse(source);
	} catch (err) {
		return newHTMLDataProvider(id, { version: 1 });
	}

	return newHTMLDataProvider(id, {
		version: rawData.version || 1,
		tags: rawData.tags || [],
		globalAttributes: rawData.globalAttributes || [],
		valueSets: rawData.valueSets || []
	});
}