This plug-in currently has two main capabilities that can be activated independently:
Scans web pages for links (in text or images) to VRML or X3D files (and other file formats compatible with the X_ITE X3D Browser, such as glTF, obj, and STL) and inserts "eye-cons" (👁) next to each of them. When you click the eye, it embeds a viewer and displays the model in 3D within the page. Right-click on an active viewer for additional options. Click the eye again to close the viewer. Supports multiple simultaneous viewers on the same page.
Be sure to visit George Hart's Encyclopedia of Polyhedra with this module enabled for a trove of beautiful models to play with.
In the late 1990s, David Joyce wrote a web applet in Java that allowed for interactive draggable 2D and 3D geometry diagrams within a page. Nearly 30 years on, Java is no longer supported for embedded applets by any major browser. This module scans web pages for invocations of that Java applet, and translates them into calls to the GeoGebra JavaScript module, bringing the diagrams back to life.
What's more, Joyce posted an on-line version of the entire Euclid's Elements with all of the traditional diagrams, and many new ones of his own creation, rendered in fully interactive versions. Be sure to give archematics a try on his site.