itch.io

This is an issue with the default package.json file I believe, which you have to edit in your game project folder. (I forgot about this step, thank you for pointing it out!)

Check if the start of the file looks like this:

{
	"name": "",
	"main": "index.html",
	"js-flags": "--expose-gc",

The updated runtime requires that the name value isn’t empty, so you can change it to something like

{
	"name": "my-game",
	"main": "index.html",
	"js-flags": "--expose-gc",

or such. (Edit: Please use a unique value! See above.) I don’t think it really matters beyond not being empty, since the title shown to the user is loaded from index.html instead.