Local Modifications
The local modifications in a WorkingDirectory are the differences existing between the files content on the filesystem and the files content in the ["Repository"] at the ["Parent"] revision.
Those differences can be displayed by a ["Diff"].
If those local modifications are committed, they will become a new ChangeSet.
When the working directory has two ["Parent"] revisions as the result of a ["Merge"], the local modifications will correspond to the resolution of the ["Conflict"]s.