Select an SVG file, and it will generate PNG icons in sizes: 16, 32, 48, and 128.
{ "manifest_version": 3, "name": "My Extension", "version": "1.0", "icons": { "16": "icon-16.png", "32": "icon-32.png", "48": "icon-48.png", "128": "icon-128.png" } }