There are some extensions that when you import the extension, 3 extensions show up together in the Extensions drawer, such as the CustomWebView : An extended form of Web Viewer - Extensions - MIT App Inventor Community extension or the https://hackernoon.com/your-kid-can-code-a-fruit-detector-with-this-mit-app-inventor-aws-ai-services-extension-231665c8bcdc extension. So you only need to download 1 file, and the project automatically loads 3 extensions together.
So far I know this is available with App Inventor sources. Is it available with Niotron IDE as well?