* Unicode::LineBreak: Handling URN-like sequences (URLs, DOI identifiers,
  e-mail addresses...).
- May inhibit breaking midst of URL-like string.
- Some standards such as "Chicago Manual of Style" recommends to break
  _before_ SOLIDUS in URL.

* Text::LineFold: (obsoleted) RFC 2646 folding and unfolding.

* Unicode::LineBreak: Interface to custom SA (Sourth-East Asian complex
  context) breaking rules.

* ``Hunging punctuation'' (ぶら下げ組み; burasage-gumi) mainly for Japanese
  texts.
- Punctuations may protrude into the right -- bottom, in vertical line --
  margin.
- It is usually applied to IDEOGRAPHIC FULL STOP and IDEOGRAPHIC COMMA.
  It is rarely applied to other punctuations; FULL STOP and COMMA.
- ``Half-''hunging, regarding ideographic punctuations as narrow only at
  end of line, might be either allowed or inhibited by typesetting rules,
  whether (full-)hunging was allowed or not.
- I. FULL STOP is more often inhibited to be narrow than I. COMMA.
- Wide (including fullwidth) parentheses may or may not ``half''-hung by
  rules, however, they shouldn't ``full''-hung anyway.

$$
