The git version control system, is a kind of distributed log (with some conceptual similarities to the raft consensus protocol).
Raft and some other systems have a concept of log compaction, so new clients don't need to traverse the whole change set to apply changes.
My question is: Does git have a concept of log compaction?
No, git is a collection of snapshots (full copy of a working tree).
When you access a commit in git, you don't have to traverse the all log or history to build its content.
See "How does git store files?": the internal storage does use delta in pack files (that is form of "compaction", not just "log compaction"), but each commit still represents the full working tree.