Hack
Hack is a programming language developed by Facebook, designed to be used with the HHVM (HipHop Virtual Machine). It is a strongly typed, high-performance language that is used primarily for building large-scale web applications.
Hello, world code example:
Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.
Repositories on GitHub: 91,755