How does Git store data internally (objects, trees, commits, blobs) and why does it matter?

Git stores content as immutable objects (blobs, trees, commits, tags) addressed by SHA-1/256, enabling efficient history, deduplication, and integrity.

Git is a content-addressable filesystem. Blobs store file contents, trees store directory structure (filenames → blob/tree hashes), commits point to a tree plus metadata (author, message, parents), and tags annotate commits. Because objects are immutable and identified by hashes, identical content is stored once, ensuring integrity and enabling cheap branching/merging. Packs compress objects for efficiency. Understanding this explains why rebases rewrite history (new commit objects) and why corruption is detectable.