git-contrib creates "git blame" based contributors report for git repositories different than the GitHub's Insights->Contributors report.
go install github.com/ermanimer/git-contrib@latest
Run following command in a git repository.
git contrib
or
git-contrib
+---------------------+------------+------------+
| author | line count | percentage |
+---------------------+------------+------------+
| ermanimer@gmail.com | 329 | 100.00 |
+---------------------+------------+------------+