The STIX 2 Pattern Validator is a software tool for checking the syntax of the
Cyber Threat Intelligence (CTI) STIX Pattern expressions, which are used within
STIX to express conditions (prepresented with the Cyber Observable data model)
that indicate particular cyber threat activity.  The repository contains source
code, an ANTLR grammar, automated tests and associated documentation for the
tool.  The validator can be used as a command-line tool or as a Python library
which can be included in other applications.