application/Espo/Core/Utils/FieldManager.php
protected function isCore($scope, $name)
    {
        $existingField = $this->getFieldDefs($scope, $name);
        if (isset($existingField) && (!isset($existingField['isCustom']) || !$existingField['isCustom'])) {
            return true;
        }

        return false;
    }
protected function isCore($scope, $name)
    {
        $existingField = $this->getFieldDefs($scope, $name);
        if (isset($existingField) && (!isset($existingField['isCustom']) || !$existingField['isCustom'])) {
            return true;
        }

        return false;
    }
protected function isCore ( $ scope , $ name ) { $ existingField = $ this -> getFieldDefs ( $ scope , $ name ) ; if ( isset ( $ existingField ) && ( ! isset ( $ existingField [ 'isCustom' ] ) || ! $ existingField [ 'isCustom' ] ) ) { return true ; } return false ; }
Check if a field is core field

@param  string  $name
@param  string  $scope
@return boolean
Check if a field is core field