How does git calculate line changes?

@rollin 

Git calculates line changes using a tool called diff, which compares two versions of a file line by line to determine the changes that have been made. The diff tool looks at each line of code in the old version of the file and the new version of the file, and identifies whether a line has been added, removed, or modified.

Git then stores this information in a diff file, which shows the changes that have been made to the file in a format that can be easily read and understood. This allows Git to track the history of changes made to a file over time, and to help resolve conflicts when multiple people are working on the same file.