get_default_upload()->name ?? '';
$input = wpcf7_array_flatten( $input );
$input = wpcf7_exclude_blank( $input );
$acceptable_filetypes = array();
foreach ( (array) $this->get_property( 'accept' ) as $accept ) {
if ( preg_match( '/^\.[a-z0-9]+$/i', $accept ) ) {
$acceptable_filetypes[] = strtolower( $accept );
} else {
foreach ( wpcf7_convert_mime_to_ext( $accept ) as $ext ) {
$acceptable_filetypes[] = sprintf(
'.%s',
strtolower( trim( $ext, ' .' ) )
);
}
}
}
$acceptable_filetype