\ExplSyntaxOn
\msg_new:nnnn {fontawesome6} {list/no-shorthand} {No~shorthand~defined~for~icon~#1.} {
  It~looks~like~#1~need~special~handling~in~fulllist.tex~but~there~are~
  no~appropriate~definitions.~Ask~a~wizard~to~add~#1~to~fulllist.tex~to~
  fix~this.
}
\tl_new:N \g__fontawesome_last_name_tl
\tl_new:N \g__fontawesome_last_cs_tl
\prg_new_protected_conditional:Nnn \__fontawesome_if_regular_style:nn {T} {
  \group_begin:
    \usefont{U}{fontawesome6#1}{regular}{n}
    \iffontchar\font#2
      \group_insert_after:N \prg_return_true:
    \else:
      \group_insert_after:N \prg_return_false:
    \fi:
  \group_end:
}
\tracingonline1
\showboxdepth\maxdimen
\showboxbreadth\maxdimen
\cs_new:Nn\__fontawesome_list_show_icon:nnnn{
  \str_if_in:nnT{#3}{brands}{
    \hfilneg\vbox to0.875em{\vfil\hbox to0pt{\hss\tiny\faTrademark\quad}\vfil}\hfil
  }
  \faIcon{#2}&\texttt{\textbackslash#1}&\texttt{\textbackslash faIcon\{#2\}}
  \str_if_in:nnT{#3}{free}{
    \__fontawesome_if_regular_style:nnT {#3} {#4} {
      \\\faIcon[regular]{#2}&\texttt{\textbackslash#1[regular]}&\texttt{\textbackslash faIcon[regular]\{#2\}}
    }
  }
  \tl_gset:Nn \g__fontawesome_last_cs_tl {#1}
  \tl_gset:Nn \g__fontawesome_last_name_tl {#2}
  \\
}
\cs_generate_variant:Nn \__fontawesome_list_show_icon:nnnn { fnnn }
\cs_set:Nn\__fontawesome_def_icon:nnnnn{
  \__fontawesome_list_show_icon:fnnn{
    \tl_if_empty:nTF{#1}{
      faIcon\{\str_foldcase:n{#2}\}
    }{
      \cs_to_str:N #1 % You might have noticed that #1 is a n-type argument, not N-type.
      % This is not a mistake, the argument might contain additional characters after the initial cs
      % which is passed to \cs_to_str:N
    }
  }{#2}{#3}{#4}
}
\ExplSyntaxOff
\newgeometry{textwidth=18cm}
\subsection*{Full~icon~list~for~FontAwesome~6~Free}
All icons marked with \vbox to0.875em{\vfil\hbox{\hss\tiny\faTrademark}\vfil} are brand icons.
\begin{quote}
  All brand icons are trademarks of their respective owners. The use of these
  trademarks does not indicate endorsement of the trademark holder by Font
  Awesome, nor vice versa. \emph{Please do not use brand logos for any purpose except
  to represent the company, product, or service to which they refer.}
\end{quote}
\ExplSyntaxOn
\begin{longtable}{cll}
  \cs:w @@input\cs_end: fontawesome6-mapping.def~
\end{longtable}
\ExplSyntaxOff
\restoregeometry
