How tagname is being used to identify version and environment

processTagNameFromController.js

var processTagName = function(tag_name) {
  var result = false;
  var tagSplit = tag_name.split('-');
  var environments = {'dev':'D', 'stage':'S', 'prod':'P'};
  if (tagSplit[0] && tagSplit[0].toLowerCase() !== 'kumo') {
    environment = 'D';
  }
  var environment = environments[tagSplit[1] ? tagSplit[1].toLowerCase() : 'dev'] || 'D';
  var version = tagSplit.slice(-1).pop();
  return {'version':version, 'environment':environment};
}