Mailspring/app/internal_packages/send-and-archive/package.json

{
  "name": "send-and-archive",
  "version": "0.1.0",
  "main": "./lib/main",
  "description": "Adds a send and archive option to the composer.",
  "license": "GPL-3.0",
  "private": true,
  "engines": {
    "mailspring": "*"
  },
  "windowTypes": {
    "default": true,
    "composer": true,
    "thread-popout": true,
    "work": true
  }
}