Many thanks for your question. Let me explain:
All the files exported by the ShapeDiver glTF exporter plugin are binary glTFs. You can choose between binary glTF 1.0 and binary glTF 2.0.
In case you choose binary glTF version 2.0 (the standard version used in the exporter, and the version we recommend to use for external geometry), then the exporter changes the file ending to .gltf instead of .glb . Don’t worry about this and don’t touch the file ending. It needs to be like this to make the files work with the external geometry component of our GH plugin, because our backend makes a distinction between glTF version 1.0 and 2.0 based on the file ending. The reason for this is that the glb loader contained in the current version of the viewer can’t differentiate by itself between versions 1.0 and 2.0. For this reason the API of the viewer defines different values for the SceneAssetItemFormat for glTF 1.0 and 2.0 (see SceneAssetItemFormat)
This is going to change in the not so far future (from viewer release 2.19.0), when the file ending is not going to matter anymore. Once the glb loader in the viewer can make the distinction between 1.0 and 2.0 itself, we will also change the exporter not to tamper with the file ending anymore.