Reflog vs Log
To view the log is to view the commit history.
$ git log --oneline
$ git log --pretty=oneline
$ git log --graph --all --oneline
log is a public accounting of the repository's commit history while the reflog is a private, workspace-specific accounting of the repo's local commits.
Reflog
The reflog is a file found in .git\logs\refs\heads that tracks the history of local commits for a given branch and excludes any commits that were potentially pruned away through Git garbage collection routines.
$ git reflog