Subnavigator source code?

From “Developing for the JIRA project-centric view” in the Jira Server Developer Guide:

The most detailed and up to date documentation around this component can be found in the source code on src/main/resources/static/components/subnavigator/Subnavigator.js.

Awesome! Where do I find that source code? I understand it’s in the Jira projects plugin, but the source code for that plugin isn’t available to outside Atlassian, or is it?

In your copy of the Jira Source, you should have this resource:

Within this jar, you’ll find the following:

That should be what you’re looking for.