src/mustache_core.js
function valueShouldBeInsertedAsHTML(value) {
	return value !== null && typeof value === "object" && (
		typeof value[toDOMSymbol] === "function" ||
		typeof value[viewInsertSymbol] === "function" ||
		typeof value.nodeType === "number" );
}
function valueShouldBeInsertedAsHTML(value) {
	return value !== null && typeof value === "object" && (
		typeof value[toDOMSymbol] === "function" ||
		typeof value[viewInsertSymbol] === "function" ||
		typeof value.nodeType === "number" );
}
DOM, safeString or the insertSymbol can opt-out of updating as text