The desktop app was removed because the devs did not like the massive size and resource usage of the desktop app, which used Electron (a heavy UI framework). As they said on their website:
While solving some of our issues, Electron was rapidly increasing in size and soon joined the rest of the software that we wanted to do away with. Our focus shifted toward reducing our energy use, and to ensure reliability by removing all dependencies.
If anyone would like to run it as a desktop app, just go to https://www.electronjs.org/ and download Electron. In the folder where you have the index.html, run the command "electron ." and you should be able to run it as a typical desktop app.