Please upload your Blend file.

That's exactly what I don't want to add.

You can disable the "Deform" option on each bone. This should already cause it to be skipped during export.

In a game, no. That's not supported.

In Source Filmmaker, yes in principle. But because the animation data format for Source Filmmaker is different from that of games, the Blender Source Tools intentionally don't target it. It's too confusing to have both at the same time.

Looks like a bad SMD file with a truncated line.

Registering this property is the very first thing the add-on does. I don't know how you got so far without it having actually worked.

You can download an older version of the tools from this page.[steamreview.org]

I'm not very interested in supporting leaked model sources. They may just be broken.

I managed to download the file. It's exactly like I told you. Two items have shape keys: "body" and "ZHANNA". So you get two VTA files, which is the correct outcome.

I don't see the point in doing this when I already host the add-on on a dedicated website, and have an updater. Going to that site and waiting for someone else to approve such a large add-on would be a drag.

What I could do is host an extension repository[docs.blender.org] and replace the current add-on updater with that.