Size & Coupling
When you open a file in the explorer, the Size & coupling row shows five plain measurements about that file. These aren’t graded good or bad on their own - they’re context. They help you understand a file’s footprint and how tied it is to the rest of the codebase.
Lines of code
The total size of the file - a quick gauge of how much is going on. Large files aren’t automatically bad, but they tend to collect complexity and duplication over time.
Logical lines of code
The amount of actual logic in the file, with blank lines and comments set aside. Two files can have the same line count but very different amounts of real work - this is the number that reflects that.
Comments
How much of the file is explanatory comments. Well-commented code is easier for the next person to pick up.
One thing to know: in languages like Python and JavaScript, docstrings are often counted as code rather than comments, so this number can read lower than you’d expect even in a well-documented file.
Fan-in (used by)
How many other files depend on this one. A high fan-in means the file is popular and important - lots of things rely on it, so changes here ripple outward and deserve extra care and testing.
Fan-out (depends on)
How many other files this one relies on. A high fan-out means the file is doing a lot of coordinating, which makes it harder to understand and to test on its own. Files with especially high fan-out show up as “hub” files in the Coupling breakdown.