manifest.json

{
  "timeZone": "America/Los_Angeles",
  "dependencies": {
    "enabledAdvancedServices": [{
      "userSymbol": "Gmail",
      "serviceId": "gmail",
      "version": "v1"
    }]
  },
  "oauthScopes": ["https://www.googleapis.com/auth/gmail.addons.execute", "https://www.googleapis.com/auth/gmail.addons.current.message.metadata", "https://www.googleapis.com/auth/gmail.modify", "https://www.googleapis.com/auth/gmail.addons.current.message.readonly"],
  "gmail": {
    "name": "Gmail Add-on Quickstart - QuickLabels",
    "logoUrl": "https://www.gstatic.com/images/icons/material/system/1x/label_googblue_24dp.png",
    "contextualTriggers": [{
      "unconditional": {
      },
      "onTriggerFunction": "buildAddOn"
    }],
    "primaryColor": "#4285F4",
    "secondaryColor": "#4285F4",
    "openLinkUrlPrefixes": ["https://mail.google.com/"]
  }
}