Routes Plugin is testing plugin for routes functionality introduced in Osclass 3.3, however may be used also in production to define routes/links those does not exists in any plugin or theme (some custom needs).
Extension has almost no visible front or backoffice functionality, however it generates new menu in oc-admin to showcase its functionality. It defines sample routes you may test:
https://yoursite.com/static-route/
https://yoursite.com/dynamic-route/123/testStringParam
This plugin can be very helpful for plugin developers those would like to check how to properly create routes.