Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
Drupal is a free and open-source web content management framework.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
MathJax is a cross-browser JavaScript library that displays mathematical notation in web browsers, using MathML, LaTeX and ASCIIMathML markup.
Ubuntu is a free and open-source operating system on Linux for the enterprise server, desktop, cloud, and IoT.
VK is a Russian online social media and social networking service.
Yandex.Metrica is a free web analytics service that tracks and reports website traffic.