I’ve added 512x512 and 144x144 icons in the Discourse settings but the manifest.json only includes one (incorrect) icon size. I have set logo url, logo small url, large icon url, apple touch icon url.
Resulting Manifest.JSON:
{
	"name": "Tallcraft Forum",
	"short_name": "Tallcraft Forum",
	"display": "standalone",
	"orientation": "any",
	"start_url": ".",
	"background_color": "#ffffff",
	"theme_color": "#ffffff",
	"icons": [{
		"src": "/uploads/default/original/1X/cc66cb57005592d19b25b66073b49c55ba020917.png",
		"sizes": "500x500",
		"type": "image/png"
	}]
}
This causes the Google Chrome PWA audit to fail:
