apply_filters( 'wp_unique_filename', string $filename, string $ext, string $dir, callable|null $unique_filename_callback, string[] $alt_filenames, int|string $number )

Parameters

$filename

Unique file name.

$ext

File extension. Example: ".png".

$dir

Directory path.

$unique_filename_callback

Callback function that generates the unique file name.

$alt_filenames

Array of alternate file names that were checked for collisions.

$number

The highest number that was used to make the file name unique or an empty string if unused.