9.42.3 Can you answer these questions?

9.42.3.1 \bm and Lualatex

https://tex.stackexchange.com/landing/r/digest?cta=question&id=689344

I just moved from PDFLatex to Lualatex. So, I am a real beginner with Lualatex and I am probably doing something wrong. 
Here is a MWE: 
\documentclass[10pt,a4paper,french]{article} 
\usepackage{... 
[luatex] [bm]
 

asked by Didier https://tex.stackexchange.com/landing/r/digest?cta=user&id=249670 Score of 1

9.42.3.2 Problem with puenc.def

https://tex.stackexchange.com/landing/r/digest?cta=question&id=689527

I have a LaTeX file processed last with texlive-2021. In this file I used 
\input{/usr/local/texlive/2021/texmf-dist/tex/latex/hyperref/puenc.def} 
to define \textsigma, \textzeroinferior, \... 
[texorpdfstring] [puence.def]
 

asked by Victor https://tex.stackexchange.com/landing/r/digest?cta=user&id=155793 Score of 1

9.42.3.3 Packages used in subfiles not working in main.tex

https://tex.stackexchange.com/landing/r/digest?cta=question&id=689376

I'm following Overleaf example of 'subfiles' 
... and also some examples of the 'verse' and the 'song' packages 
The subfiles work well but when called by main.tex the song package does not work ... 
[subfiles] [verse] [songs]
 

asked by AWE https://tex.stackexchange.com/landing/r/digest?cta=user&id=223343 Score of 1