The definition of 'user inactivity' contains a sentence that reads as a note, but that sentence isn't marked up as a note.

user inactivity

any continuous period of time where no user actions occur

The method of tracking will be determined by the web site or application.

should instead look like this:

user inactivity

any continuous period of time where no user actions occur

NOTE
The method of tracking will be determined by the web site or application.