code: def get_filename_extensions(url='https://www.webopedia.com/quick_ref/fileextensionsfull.asp'):
      
      df = get_longest_table(url)
      columns = list(df.columns)
      columns[0] = 'ext'
      columns[1] = 'description'
      if len(columns) > 2:
          columns[2] = 'details'
      df.columns = columns
      return df
docs: Load a DataFrame of filename extensions from the indicated url
  
      >>> df = get_filename_extensions('https://www.openoffice.org/dev_docs/source/file_extensions.html')
      >>> df.head(2)
          ext                      description
      0    .a        UNIX static library file.
      1  .asm  Non-UNIX assembler source file.