Insert and Send HTML with Gmail

{
    "update_url": "https:\/\/clients2.google.com\/service\/update2\/crx",
    "name": "Insert and Send HTML with Gmail",
    "short_name": "Insert and Send HTML with Gmail",
    "description": "Easily insert custom HTML into your Gmail emails with this handy extension. Create and preview your custom emails directly in Gmail.",
    "version": "1.0.13",
    "permissions": [
        "scripting",
        "tabs",
        "activeTab"
    ],
    "host_permissions": [
        "*:\/\/mail.google.com\/*",
        "*:\/\/inbox.google.com\/*"
    ],
    "content_scripts": [
        {
            "matches": [
                "*:\/\/mail.google.com\/*",
                "*:\/\/inbox.google.com\/*"
            ],
            "js": [
                "js\/content.js"
            ],
            "css": [
                "css\/content.css"
            ]
        }
    ],
    "background": {
        "service_worker": "js\/background.js"
    },
    "icons": {
        "16": "icons\/16.png",
        "48": "icons\/48.png",
        "128": "icons\/128.png"
    },
    "web_accessible_resources": [
        {
            "resources": [
                "resources\/*"
            ],
            "matches": [
                "*:\/\/mail.google.com\/*",
                "*:\/\/inbox.google.com\/*"
            ]
        }
    ],
    "manifest_version": 3
}