def get_filename_extensions(url='https://www.webopedia.com/quick_ref/fileextensionsfull.asp'):
    """ 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.
    """
    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
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.