> Whenever a new push event is detected, the lines that are changed in each of the commits in the push event are collected and stored

I think it's important to realize that some languages tend to have more lines of code to achieve the same things as in other languages, and AFAICT this doesn't take that into account. I don't think lines of diff is a reliable metric for "Language Popularity"...

For example, the #2 and #3 languages (Java and C# respectively) have some ceremonial lines of getters and setters. Consider the problem "find the area of a square". In Java or C#, one would often write a class like this:

    public class Square {
        double side;

        Square(double s) {
            side = s;
        }
        void setSide(double s) {
            side = s;
        }
        double getSide() {
            return side;
        }
        double getArea() {
            return side * side;
        }
    }

OTOH, someone writing bash (language #19 in terms of popularity is "Shell") might write something like this:

    #!/bin/bash
    square() {
        echo "$(($1 * $1))";
    };