insomnia/packages/insomnia-app/app/datasets/header-names.js

export default [
  'Content-Type',
  'Content-Length',
  'Accept',
  'Accept-Charset',
  'Accept-Encoding',
  'Accept-Language',
  'Accept-Datetime',
  'Authorization',
  'Cache-Control',
  'Cookie',
  'Connection',
  'Content-MD5',
  'Date',
  'Expect',
  'Forwarded',
  'From',
  'Host',
  'If-Match',
  'If-Modified-Since',
  'If-None-Match',
  'If-Range',
  'If-Unmodified-Since',
  'Max-Forwards',
  'Origin',
  'Pragma',
  'Proxy-Authorization',
  'Range',
  'Referer',
  'TE',
  'User-Agent',
  'Upgrade',
  'Via',
  'Warning',
];