This is an old revision of the document!
As an exercise in toning your abstraction abilities (literally seeing one thing, but understanding and using it as something else), there will be a number of 'generic' terms used throughout this (and other) documents throughout the course, requiring you to substitute in the pertinent information (else face confusion or error).
Some examples:
This sort of abstraction is very similar to that we will find in our utilization of variables in programming, where we can have a “name”, but the data associated with it can change based on various conditions.
Do not be a literalist computer! Start to exercise your abstraction abilities.