10.78.3 Can you answer these questions?

10.78.3.1 Debugging (tracing) pgfplots sample point coordinates

https://tex.stackexchange.com/landing/r/digest?cta=question&id=731767

Is there a way to debug (trace to the log file) coordinates of sample points or any intermediate calculations. For example, \addplot3 used below uses 3 points (0,0,2), (1,0,1) and (2,0,0) to draw the ... 
[pgfplots] [debugging]
 

asked by Sergei Zinovyev https://tex.stackexchange.com/landing/r/digest?cta=user&id=294709 Score of 1

10.78.3.2 moderncv subsection error while using Font Awesome icons

https://tex.stackexchange.com/landing/r/digest?cta=question&id=731381

I want to use Font Awesome icons in my moderncv sections and subsections. 
For the sections, I could solve the upcoming font error 
LaTeX Font: Font shape `T1/cmss/b/n' undefined 
(Font)  using `T1/cmss/... 
[fonts] [moderncv] [subsection]
 

asked by V1P3R https://tex.stackexchange.com/landing/r/digest?cta=user&id=358594 Score of 1

10.78.3.3 Very strange \edef l3backend-luatex.def Foo  or \edef a^\237..file namea^\237(c) Foo  (not created by me)

https://tex.stackexchange.com/landing/r/digest?cta=question&id=731762

(This is a follow-up of a previous question of mine.) 
The following MCE works as expected: 
\documentclass{article} 
\begin{document} 
\ExplSyntaxOn 
\cs_new_protected:Nn \_add_data:n { 
% Here, we use ... 
[expansion]
 

asked by Denis BitouzA~(c) https://tex.stackexchange.com/landing/r/digest?cta=user&id=18401 Score of 2