The submission form seems outdated-the rules state that a HTML5 format is fine, but that's absent in the form.

In addition, is the discord username required? I am also confused about the "Participation Level", and I would appreciate you clarifying.

Thanks!

It's not outdated. An HTML5 version is fine as it's playable on all 3 platforms.
Discord username is required. If not applicable, put n/a instead. Participation level is how many time have you participated in Godot Wild Jam. There's also a question of how many jams to gauge if you are a beginner or not.

Thank you for clarifying this - I wouldn't have guessed those without description. Jams should explain form filling in rules so that there won't be last minute surprises. Or just use clearer language eg "no. of jams participated".