What does the "skipUncaughtErrors" flag mean by server?

In the TestCafe documentation the skipUncaughtErrors flag mentions: uncaught error or unhandled promise rejection occurs on the server during test execution.

What is meant by server here?

I found this flag after we started getting an issue quite randomly, with very little to debug from:

    1) - Error in fixture.beforeEach hook -
       Unhandled promise rejection:
 
       Error: [eval("")] Not JSON response
       at exports.newError

Figured it was worth a try to set skipUncaughtErrors: true and we haven't seen that issue since. Nonetheless, the team is worried about using features we don't understand. :)