The parent dependency is used for zones or other child images. In this case, the dependency is only checked in the child image, and specifies a package and version that must be present in the parent image or global zone. The version specified must match to the level of precision specified.
For example, if the parent dependency is on A@2.1, then any version of A beginning with 2.1 matches. This dependency is often used to require that packages are kept in sync between non-global zones and the global zone. As a shortcut, the special package name feature/package/dependency/self is used as a synonym for the exact version of the package that contains this dependency.
The parent dependency is used to keep key operating system components, such as libc.so.1, installed in the non-global zone synchronized with the kernel installed in the global zone. The parent dependency is also discussed in Chapter 10, Handling Non-Global Zones.
An example parent dependency is:
depend type=parent fmri=feature/package/dependency/self \
variant.opensolaris.zone=nonglobal