This is how you remove unwanted files and/or directories from commit history on github.com.

githhub-clean-branch-history.log

  # Get your files ignored correctly on the file system and website, keep checking until
  # the latest commit is perfect.
 
  639  vi ./.gitignore 
  640  git rm -r --cached . 
  641  git add -A
  642  git commit -m "adding"
  643  git push origin master
  
  # now create a temp branch off master, then delete the master, and push master back up again.
  # https://tecadmin.net/delete-commit-history-in-github/
  653  git checkout --orphan temp_branch
  654  git branch
  655  git add -A
  656  git commit -am "the first commit"
  657  git branch -D master
  658  git branch -m master
  659  git push -f origin master
  
  # presto -- all those commits are gone on the website.