YANG features, including configuration hierarchy must constraints published in YANG, and a module that defines Junos OS YANG extensions

The Juniper Networks configuration YANG module includes configuration constraints published using either the YANG must statement or the Junos OS YANG extension junos:must. Constraints that cannot be mapped directly to the YANG must statement, which include expressions containing special keywords or symbols such as all, any, unique, $, __, and wildcard characters, are published using junos:must. The Junos OS extensions YANG module contains definitions for Junos OS extensions, including the must and must-message keywords.