Gitea is an open-source forge software package for hosting software development version control using Git as well as other collaborative features like bug tracking, wikis and code review. It supports self-hosting but also provides a free public first-party instance hosted on DiDi's cloud.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Nginx is a web server that can also be used as a reverse proxy, load balancer, mail proxy and HTTP cache.
Open Graph is a protocol that is used to integrate any web page into the social graph.
Progressive Web Apps (PWAs) are web apps built and enhanced with modern APIs to deliver enhanced capabilities, reliability, and installability while reaching anyone, anywhere, on any device, all with a single codebase.