I've downloaded a copy of iOS source code and there is a .mom file in the bundle. I just know it is a "product" of NSManagedObjectModel. I wonder is there any way that I can explore the entities in the file, or is there any code snippet to parse its structure. Thank you!
Use the managed object model decompiler [full disclosure: I wrote it] to convert the .mom back into a .xcdatamodel. Then open the result in Xcode.