HEAD

The HEAD is a special dynamic reference pointing to the branch you’re currently working on. It can be used when the latest checked out commit has to be referenced.

        gitGraph
    commit
    branch origin/feature-a
    commit
    commit
    commit
    branch BranchA
    checkout BranchA
    commit
    commit
    checkout main
    merge BranchA id: "HEAD"
    

Example from the last chapter showing HEAD

Most git commands default to HEAD if no reference or hash is passed as an argument.

For example:

git show --stat HEAD
# is the same as
git show --stat