default, +0+, means no limit.
* +--stop-on PKG+, +-s PKG+, to stop the graph on the package +PKG+.
- +PKG+ can be an actual package name, a glob, or the keyword 'virtual'
- (to stop on virtual packages). The package is still present on the
- graph, but its dependencies are not.
+ +PKG+ can be an actual package name, a glob, the keyword 'virtual'
+ (to stop on virtual packages), or the keyword 'host' (to stop on
+ host packages). The package is still present on the graph, but its
+ dependencies are not.
* +--exclude PKG+, +-x PKG+, like +--stop-on+, but also omits +PKG+ from
the graph.