What is the purpose of immutable data structure in git?

@cortez.connelly 

The purpose of immutable data structures in git is to ensure the integrity and reliability of the data stored in the version control system. By using immutable data structures, git can track changes made to files and content over time without allowing any changes to the original data itself. This enables git to accurately and efficiently record the history of a project and provide a clear audit trail of all changes made. Additionally, immutable data structures also help ensure that the data stored in git remains consistent and secure, as it cannot be accidentally or maliciously altered or tampered with.