With escaping for special characters can these exceed 512 bytes for

char output[512];  // Stack buffer - UNSAFE!
constexpr size_t outputSize = sizeof(output);

Could you explain more about this issue @swwilshub? "Character" probably want's the right word to use in the title, it should really be "byte", we're allocating a 500 byte array for the title and then calling file.getName on the file, from the docs of getName:

  /**
   * Get a file's name followed by a zero byte.
   *
   * \param[out] name An array of characters for the file's name.
   * \param[in] len The size of the array in bytes. The array
   *             must be at least 13 bytes long.  The file's name will be
   *             truncated if the file's name is too long.
   * \return The length of the returned string.
   */

So for files with names longer than 500 bytes, we'd just get a truncated name as before. These changes don't fully solve the issue, but extending it to 500 bytes seems like an acceptable limit to me atm.