The first line (or atleast, the first 80 characters) should be a quick summary - so you can quickly browse via git blame.
But the actual commit message should consist of History/Motivation/Context - so that someone who's going through the blame can understand why a certain change was made, and what the context was.
But the actual commit message should consist of History/Motivation/Context - so that someone who's going through the blame can understand why a certain change was made, and what the context was.
Linus had a good template for this, which makes a lot of sense: https://gist.github.com/finalfantasia/bd0070673ca27e5f7473