I embedded a sequence of .bgeo files in the Extra Files section of my asset. Now I'd like to load them with the File SOP (via opdef). However I cannot find those files anywhere in the opdef hierarchy. I can see the folder of my asset in the opdefObject dir, however when I dive in it, it's blank (the Look in address bar turns red and I get “Directory does not exist” in place of the files list.

I think it's important to mention that the asset is namespaced. I used naming convention described in the documentation:
node_name
So I have something like this:
com.mynamespace::asset_name::1.0

The problem does not seem to happen with assets that don't use namespaces like: asset_name, asset_name::1.0.

What am I doing wrong? How can I access extra files from namespaced assets?

The opdef browser seems broken for namespaced assets. :?
The opdef syntax should actually be:
opdef:awong::Object/foo::1.0?box.bgeo
If you enter:
opdef:awong::Object/foo::1.0
into the “Look in” directory, you can get the browsing to work.

We've just made a fix for this issue. Give it a try in tomorrow's build (15.0.315).

awong
We've just made a fix for this issue. Give it a try in tomorrow's build (15.0.315).

You Sir are pure gold! The bearer of good news. Thank you.
And please pass my thanks to the whole team for such a rapid fix!