code: public function getExceptionByIdentifier($identifier)
      {
          $key = strtolower($identifier);
  
          if (!isset($this->exceptions[$key])) {
              return;
          }
  
          list($identifier, $name) = $this->exceptions[$key];
  
          return array(
              $name,
              'https://spdx.org/licenses/' . $identifier . '.html#licenseExceptionText',
          );
      }
docs: Returns license exception metadata by license exception identifier.
  
  This function adds a link to the full license exception text to the license exception metadata.
  The array returned is in the form of:
  
  [ 0 => full name (string), 1 => link to license text (string) ]
  
  @param string $identifier
  
  @return array|null