showExtensions config param

src/core/index.js

@@ -47,6 +47,7 @@ module.exports = function SwaggerUI(opts) {
     showMutatedRequest: true,
     defaultModelRendering: "example",
     defaultModelExpandDepth: 1,
+    showExtensions: false,
 
     // Initial set of plugins ( TODO rename this, or refactor - we don't need presets _and_ plugins. Its just there for performance.
     // Instead, we can compile the first plugin ( it can be a collection of plugins ), then batch the rest.