In this project, a basic Theia editor is set up with basic config. All you can do right now is create and modify files present in this Glitch project, which you can do by clicking File > Open Workspace > Choose directory you want to edit. BECAUSE OF THIS, ANYONE CAN EDIT, DELETE, MODIFY, AND ADD FILES TO THE PROJECT THE EDITOR IS LOCATED IN UNLESS THE EDITOR IS PROTECTED USING A PASSWORD OR BY SOME OTHER MEANS.
While Theia runs perfectly OK on an unboosted project, a boosted project is recommended for best experience. It used approximately 70% of my disk space, almost 30% of my memory and very less CPU. These values were for a single user visiting the project, these values might increase if more users visits the project.
You can customize the Theia editor even more (like the ability to add VSCode extensions and editor themes), see the documentation for more info: https://theia-ide.org/docs/
Yeah, it does take time to finish installing the plugins and packages and start serving the editor. I left the editor in another tab, watched Minecraft gameplays (by Dream) and then came back after some time and it finished installing.