Njs is an nginx module that extends the server's functionality through
JavaScript scripting, enabling the creation of custom server-side logic.

Use cases:
- Complex access control and security checks in njs before a request
  reaches an upstream server
- Manipulating response headers
- Writing flexible asynchronous content handlers and filters

This port only installs the module sources.  The module itself is built
by the nginx ports when their NJS option is enabled.