git branch is a Git command used to list, create, or delete branches in a Git repository. When used with no arguments, it lists all existing branches in the repository.

Here’s an example of how git branch can be used:

$ git branch
* master
  development
  feature-123

In this example, the git branch command is used to list all the branches in the repository. The * character indicates the currently checked out branch, which is master in this case. The other branches listed are development and feature-123.

You can also use git branch with additional arguments to create or delete branches. For example, to create a new branch called new-feature, you can run:

$ git branch new-feature

And to delete a branch called old-feature, you can run:

$ git branch -D old-feature

I hope this helps! Let me know if you have any other questions.