What are non-standard interfaces for desktop applications based on?

Question

Design

What do non-standard designs of desktop applications write on?
Examples include programs such as Steam (desktop client) and Discord.

Answer 1

For example, Discord is written in electron. For greater clarity, the electron developers on the site have a list of applications written on it https://electronjs.org/apps

Answer 2

Electron also has a competitor nw.js as an addition, now for a long time many desktops are written in a bunch of js + html + css, because the main logic is on the servers, and the desktop acts as a client