Git does use deltas for storage.
This way it can (often, depends on the heuristics) take advantage of other similar files or older versions that are more similar than the previous. The "pack window" parameter allows trading performance for delta compression quality.
Does git only store deltas?
Git does use deltas for storage.
Not only that, but it's more efficient in it than any other system.
What is a Delta in git?
Git uses Delta encoding which indicates a way of storing or transmitting data in the form of differences (deltas) between sequential data rather than complete files. An object in a pack is stored as a delta i.e. a sequence of changes to make to some other object.
