Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Analytics is a free web analytics service that tracks and reports website traffic.
OpenGSE is a test suite used for testing servlet compliance. It is deployed by using WAR files that are deployed on the server engine.
Twitter is a 'microblogging' system that allows you to send and receive short posts called tweets.
Unpkg is a content delivery network for everything on npm.