I will explain what deep means.
For example, I am working on a program that needs some functions of SLAM. I can learn SLAM theory from an open class. There is a lot on Youtube. But, they are not helpful because it is impossible to write a fully functional SLAM program from scratch. There is usually no time for this in a real program.
If you think that why not begin from some exited frameworks, e.g., Cartographer and SLAM toolbox? Well, it is a good idea but it is also not easy. These open code lakes documents. The code itself is certainly not ready for any specific program. Some functions should be added and some should be removed. The consequence is that it is also very time-consuming to read the codes. The worse is that these codes are usually written by geniuses whose programming skills are much better than mine. I cannot understand all of them.
There needs a class that is teaching these open frameworks. Not only to teach how to use them but also to teach how these frameworks are working. What are the most important objects in these frameworks, and what are these functions can do?