.gitconfigs per directory or repo

.gitconfig

# As of git version 2.13, git supports conditional configuration includes.
# In this example we clone Company A's repos in ~/company_a directory, and Company B's repos in ~/company_b.

[user]
  name = John Smith
  email = john.smith@example.com

# If the pattern ends with /, ** will be automatically added.
# For example, the pattern foo/ becomes foo/**. In other words, it matches "foo" and everything inside, recursively.
[includeIf "gitdir:~/company_a/"]
  path = .gitconfig-company_a

.gitconfig-company_a

# You can set new values or override those in .gitconfig

[user]
  name = J.Smith
  email = jsmith@companya.com