I'd argue "why a method exists" should be addressed with naming and javadocs, not in the commit message. Why split the meaning of the code between the code itself and the commit messages?
And if it's not possible to document inline, the PR docs or code review comments should address this. Then future onlookers can use `blame` to see the context.
And if it's not possible to document inline, the PR docs or code review comments should address this. Then future onlookers can use `blame` to see the context.