See perlrebackslash
a little help from PPIx::Regexp::Token::Literal and wxPPIxregexplain.pl
xRe::Token::Literal
a literal character
ordinal= ord( chr( 10 ) ) alias \N{U+000A} alias \012 alias LINE FEED (LF) alias
\x{A}
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ordinal= ord( chr( 11 ) ) alias \N{U+000B} alias \013 alias LINE TABULATION
\x{B}
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ordinal= ord( chr( 12 ) ) alias \N{U+000C} alias \014 alias FORM FEED (FF) alias
\x{C}
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ordinal= ord( chr( 13 ) ) alias \N{U+000D} alias \015 alias CARRIAGE RETURN (CR) alias
\x{D}
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ordinal= ord( chr( 8232 ) ) alias \N{U+2028} alias \20050 alias LINE SEPARATOR alias
\x{2028}
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ordinal= ord( chr( 8233 ) ) alias \N{U+2029} alias \20051 alias PARAGRAPH SEPARATOR alias
\x{2029}