'<branchname>@\{upstream\}', e.g. 'master@\{upstream\}', '@\{u\}'::
The suffix '@\{upstream\}' to a branchname (short form '<branchname>@\{u\}')
refers to the branch that the branch specified by branchname is set to build on
- top of. A missing branchname defaults to the current one.
+ top of (configured with `branch.<name>.remote` and
+ `branch.<name>.merge`). A missing branchname defaults to the
+ current one.
'<rev>{caret}', e.g. 'HEAD{caret}, v1.5.1{caret}0'::
A suffix '{caret}' to a revision parameter means the first parent of