upquote { upright-quote and grave-accent glyphs in verbatim

By default, the LTEX \verb macro and verbatim environment display ASCII characters 27 and 60 as ’ and ‘, respectively, in line with how these two characters are used to typeset opening and closing quotation marks elsewhere in TEX. However, the character-set standards define character 27 to represent a straight single quotation mark ' and character 60 as a grave accent `. This is what most modern fonts show, and what readers of software source code are now likely to expect [1, 2]. The curly quotation mark characters ‘ and ’ are instead associated with Unicode positions U+2018 and U+2019.