Pattern is used to generate default path when files are saved via download configuration dialog.

Nullable special character can be enclosed in <>, so this part would be removed from path when corresponding value is absent.

The default pattern is \c-<\b->\t.

On 2ch.hk/mobi/625219 the pattern will be replaced with dvach-mobi-625219.

On arhivach.org/117403 the pattern will be replaced with arhivach-117403: optional null- part is removed since this forum doesn't have boards.