5.28.3 Can you answer these questions?

5.28.3.1 Why pdfcsplain format breaks with \frlang?

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=505206

Outlook and copy/paste of pdfcsplain run on the following file works well: 
\input utf8lat1 \input lmfonts 
A~\252 A~(c) A~ 
\end 
Outlook and copy/paste of pdfcsplain run on the following file is broken: 
... 
[csplain] [enctex]
 

asked by Igor Liferenko https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=70900 1 vote

answered by egreg https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=4427 0 votes

5.28.3.2 Feynman diagram: overlapping momenta and arrows

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=505014

I have the following piece of code: 
\documentclass[11pt]{article} 
\usepackage{tikZ-feynman} 
\use[ackage{amsmath} 
\begin{document} 
\feynmandiagram 
[horizontal=d to f1] { 
% Draw the top and bottom  ... 
[tikz-feynman] [feynman]
 

asked by Rethliopuks https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=121681 1 vote

5.28.3.3 Make xparse not gobble end of line character on optional argument

https://tex.stackexchange.com/landing/r/newsletter?cta=question&id=504690

When using xparse to define a new environment with an optional argument O{}, the first end of line character is gobbled as can be seen in the following example document: 
\documentclass{article} 
... 
[xparse] [white-space]
 

asked by siracusa https://tex.stackexchange.com/landing/r/newsletter?cta=user&id=23765 1 vote