What composes them?
The tree object (hash of the commit's actual content)
Hash of the parent commit
Author name and timestamp of authoring
Commiter name and timestamp of commit
What are the consequences on the rebase?
Reapply commits on top of another base tip
Elementary my dear Watson?
git rebase <target>
re-base the current branch on the top of target
What will be moved on top of <target> and what won't?
Find all the commits in the current branch not in target
move the HEAD of the branch to target (reset)
Apply all the commits found in step 1 on top of the branch
How does collaborative work with rebase?
See more: rebase with merges