Team & Enterprise Admins have the option of keeping track of time spent learning for their team. Here is how articles are represented there.
On all article information cards (when viewed in search, library, or in sections of learning) there is an estimated time to read metric, like here:
Each minute of learning is the equivalent of this estimation of time it takes to read through the article. So, if a team member reads through SwiftLint in Depth and marks the article as completed, then they have an additional 30 minutes of learning reflected in the Admin dashboard.