_loadTheme = function( tFolder ) {

  const themeJsonPath = PATH.join(tFolder, 'theme.json'); // [^1]
  const exists = require('path-exists').sync;

  // Create a FRESH or JRS theme object
  const theTheme =
    exists(themeJsonPath)
    ? new FRESHTheme().open(tFolder)
    : new JRSTheme().open(tFolder);

  // Cache the theme object
  _opts.themeObj = theTheme;
  return theTheme;
}
Load the specified theme, which could be either a FRESH theme or a JSON Resume
theme (or both).