This extension helps web masters to test web application behaviour with Content Security Policy version 2.0 implemented.
What is CSP Tester?
CSP Tester is a Firefox add-on that helps web masters test web application behavior with Content Security Policy version 2.0 implemented. It allows for easy testing of the application's adherence to the security policy and identification of potential vulnerabilities.
CSP Tester is risky to use as it requires a number of sensitive permissions that can potentially harm your browser and steal your data. Exercise caution when installing this add-on. Review carefully before installing. We recommend that you only install CSP Tester if you trust the publisher.
CSP Tester has earned a fairly good reputation and likely can be trusted.