function findAttributeTargets(elt, attrName) {
    const attrTarget = getClosestAttributeValue(elt, attrName)
    if (attrTarget) {
      if (attrTarget === 'this') {
        return [findThisElement(elt, attrName)]
      } else {
        const result = querySelectorAllExt(elt, attrTarget)
        if (result.length === 0) {
          logError('The selector "' + attrTarget + '" on ' + attrName + ' returned no matches!')
          return [DUMMY_ELT]
        } else {
          return result
        }
      }
    }
  }
@param {Element} elt
@param {string} attrName
@returns {(Node|Window)[]}