Discounting the last punctuation mark in one character at the end of the line
The setting of -ah-avoid-widow-word: true in CJK prevents the last line of a paragraph from being just one character. At this time, you can specify whether to count the punctuation mark including in the last character by -ah-avoid-widow-words-cjk-punctuation. This feature is available from AH Formatter V7.1.
For details about ‘axf:avoid-widow-word’ see “Widow Adjustment of Paragraphs (axf:avoid-widow-words)” in Lines.

-ah-avoid-widow-words-cjk-punctuation: false;

Because the punctuation mark is also counted as one character, they may be lines like “る。”
PDF が普及した要因のひとつは、PDF の仕様書が「PDF Reference」として PDF 誕生当初から公開されてきたことである。

-ah-avoid-widow-words-cjk-punctuation: true;

Because punctuation marks are not counted in one character, they do not become a line like “る。”, but a line like “ある。”. The target punctuation marks here are characters classified as CL or CP in UAX#14: Line Breaking Properties (such as closing parenthesis and punctuation mark), U+2019 and U+201D.
PDF が普及した要因のひとつは、PDF の仕様書が「PDF Reference」として PDF 誕生当初から公開されてきたことである。

-ah-avoid-widow-words-cjk-punctuation: <string>

If you specify a character string other than ‘true’ or ‘false’, such as -ah-avoid-widow-words-cjk-punctuation: '?!', those characters will also be treated as the target punctuation in addition to the above.
PDF が普及した要因のひとつは、PDF の仕様書が「PDF Reference」として PDF 誕生当初から公開されてきたことである。

-ah-avoid-widow-words-cjk-punctuation: auto

If -ah-avoid-widow-words-cjk-punctuation: auto is specified, follows the setting of ‘-ah-avoid-widow-words-cjk-punctuation’ in the Option Setting File.