It's a clunky website, but what you want is listed under the data structs located here. If you are familiar with Collada, Blender organizes its data in a similar fashion. The root tree has arrays of stuff (the main library), and then you just work your way inwards. One thing to note is that "objects" are entities in the world that reference something real, like a mesh or a lamp. However, in Blender if you SHIFT-D to make a copy of an object, you are also making a copy of the mesh (or lamp or whatever). Obviously that's not very efficient. You only really need one copy of a mesh, so make sure to use ALT-D instead. This will create a new object, but reference the mesh instead, which will be much more efficient for you to parse and work with.