I am so sorry, I did overlook your answer here somehow.
So we can access Content Browser through C++? Like select objects in content browser and open it in C4D?
The answer to that depends a bit on how you mean the quoted part. Just like for most other modules and libraries, the SDK does not expose the manger itself, but the logic behind it. So, the
SDKBrowser cannot remote control the content browser manager, by for example, opening menus, pressing buttons, etc. in it. Instead it will provide an interface which exposes the important functionalities of the content browser on a more abstract level.
There are quite a few types involved with Browser library, the most important ones in this case being the SDKBrowser type, which effectively acts like a database interface, and SDKBrowserContentNode, which is the major ressource element in such database. Via
SDKBrowser you can add, remove or search for nodes and more. In case this did not clarify your questions, I would reccomend having a look at the type definitions in order to find out if it can do what you need.
You can view files in content browser with just fbx or obj files. It doesn't have to be in lib4d format.
So you want to use it like a file manger, i.e., without an index file, e.g. lib4d, which binds all the assets together? The asset browser works here indeed differently, but as I said, the content browser is still around, if you are after a file manger within Cinema 4D.