My blog series refers to the rig since it wasn’t deprecated at the time.
Part 5 talks about how you replace a function of the Developer Rig with an external server to serve your files (as that was a function the dev rig could do).
That server could be used in the now deprecated rig via a “start frontend server with a command”.
Then you need to trace and debug your extension and find out why these events are not being called.
Not sure what this.twitchHelper is here either, which suggest some sort of framework. Did that framework init in time and not cause a Twitch to go “something is wrong extension did not load in time”
So you need to open developer tools and trace why your javascript isn’t running. Did your HTML actually load?
Debugging an extension is the same as debugging a regular website, since at the end of the dat an extension is just a website with a couple of requriements.