Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Python is an interpreted and general-purpose programming language.
PythonAnywhere is an online integrated development environment (IDE) and web hosting service (Platform as a service) based on the Python programming language.