AMP, originally created by Google, is an open-source HTML framework developed by the AMP open-source Project. AMP is designed to help webpages load faster.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Open Graph is a protocol that is used to integrate any web page into the social graph.