BambuConnect is not part of BambuStudio - That's intentional, so BambuLab does not need to share/open-source it.
The current implementation (the Bambu network plugin thingy) isn't a part of it either, it's downloaded by the client when BambuStudio is opened.
They claimed that studio wouldn't need connect.
I don't know AGPL well enough to know if a plugin is considered a derived work but it sure seems to imply it:
> For example, Corresponding Source includes interface definition files associated with source files for the work, and the source code for shared libraries and dynamically linked subprograms that the work is specifically designed to require, such as by intimate data communication or control flow between those subprograms and other parts of the work.
It's licensed under the Affero GPL which is very strict about the licensing of derived works. That license requires Bambu to include the source code to any additions they make, including all of the logic, keys, etc. that they're baking into any binary distributions. If they don't, they're violating the copyright rights of Prussa and many others.
So, either Bambu has to open source all of this, which defeats the purpose (given that it's already leaked, that's gonna happen anyway) or they have to route everything through a separate program for their own slicer.