Warning: this is an htmlized version!
The original is here, and
the conversion rules are here.
% (find-LATEX "2020list-test.tex")
% (defun c () (interactive) (find-LATEXsh "lualatex -record 2020list-test.tex" :end))
% (defun C () (interactive) (find-LATEXSH "lualatex 2020list-test.tex" "Success!!!"))
% (defun D () (interactive) (find-pdf-page      "~/LATEX/2020list-test.pdf"))
% (defun d () (interactive) (find-pdftools-page "~/LATEX/2020list-test.pdf"))
% (defun e () (interactive) (find-LATEX "2020list-test.tex"))
% (defun u () (interactive) (find-latex-upload-links "2020list-test"))
% (defun v () (interactive) (find-2a '(e) '(d)))
% (defun cv () (interactive) (C) (ee-kill-this-buffer) (v) (g))
% (defun d0 () (interactive) (find-ebuffer "2020list-test.pdf"))
%          (code-eec-LATEX "2020list-test")
% (find-pdf-page   "~/LATEX/2020list-test.pdf")
% (find-sh0 "cp -v  ~/LATEX/2020list-test.pdf /tmp/")
% (find-sh0 "cp -v  ~/LATEX/2020list-test.pdf /tmp/pen/")
%   file:///home/edrx/LATEX/2020list-test.pdf
%               file:///tmp/2020list-test.pdf
%           file:///tmp/pen/2020list-test.pdf
% http://angg.twu.net/LATEX/2020list-test.pdf
% (find-LATEX "2019.mk")
% (find-lualatex-links "2020list-test" "{tla}")

\documentclass[oneside]{book}
%\usepackage[colorlinks,urlcolor=DarkRed]{hyperref} % (find-es "tex" "hyperref")
%\usepackage{amsmath}
%\usepackage{amsfonts}
%\usepackage{amssymb}
%\usepackage{pict2e}
%\usepackage[x11names,svgnames]{xcolor} % (find-es "tex" "xcolor")
%\usepackage{colorweb}                 % (find-es "tex" "colorweb")
%\usepackage{tikz}
%
% (find-dn6 "preamble6.lua" "preamble0")
%\usepackage{proof}   % For derivation trees ("%:" lines)
%\input diagxy        % For 2D diagrams ("%D" lines)
%\xyoption{curve}     % For the ".curve=" feature in 2D diagrams
%
%\usepackage{edrx15}               % (find-LATEX "edrx15.sty")
%\input edrxaccents.tex            % (find-LATEX "edrxaccents.tex")
%\input edrxchars.tex              % (find-LATEX "edrxchars.tex")
%\input edrxheadfoot.tex           % (find-LATEX "edrxheadfoot.tex")
%\input edrxgac2.tex               % (find-LATEX "edrxgac2.tex")
%
% (find-es "tex" "geometry")
\usepackage{lipsum}                % (find-es "tex" "lipsum")
\begin{document}

% (find-es "tex" "list")
% (find-es "tex" "quotation")
% (find-source2epage (+ 10 292) "55     List, and related environments")
% (find-source2etext (+ 10 292) "55     List, and related environments")
% (find-source2epage (+ 10 292) "55     List, and related environments" "quotation")
% (find-source2etext (+ 10 292) "55     List, and related environments" "quotation")
% (find-source2epage (+ 10 294) "55.2    Vertical Spacing (skips)")
% (find-source2etext (+ 10 294) "55.2    Vertical Spacing (skips)")

\newcounter{mycounter}

\def\listtest#1#2{
#1
\begin{list}{\arabic{mycounter}.}%
  {\usecounter{mycounter}#2}
  \item \lipsum[1][1-3]
  \item \lipsum[2][1-3]
  \item[(Foo)] \lipsum[3][1-3]
  \item[(FooBar)] \lipsum[4][1-3]
  %\item \lipsum[3][1-2]
\end{list}
}

\lipsum[3-9][4-8].


\listtest{itemsep 0pt:}{%
  \setlength\itemsep{0pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }

\listtest{itemsep 10pt:}{%
  \setlength\itemsep{10pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }

\listtest{parsep 0pt itemsep 0pt topsep 0pt:}{%
  \setlength\topsep{0pt}
  \setlength\parsep{0pt}
  \setlength\itemsep{0pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }

TEST:
\begin{list}{\arabic{mycounter}.}%
  {\usecounter{mycounter}
   \setlength\topsep{0pt}
   \setlength\parsep{0pt}
   \setlength\itemsep{0pt}
  }
  \item \lipsum[1][1-2]
  \item \lipsum[2][1-2]
  \item \lipsum[3][1-2]
\end{list}



\listtest{parsep 0pt itemsep 0pt:}{%
  \setlength\parsep{0pt}
  \setlength\itemsep{0pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }

\listtest{parsep 0pt:}{%
  \setlength\parsep{0pt}
  %\setlength\itemsep{0pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }

\listtest{parsep 10pt:}{%
  \setlength\parsep{10pt}
  %\setlength\itemsep{10pt}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{0pt}
  }




\listtest{leftmargin 0pt:}{%
  %\setlength\itemsep{2ex}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  \setlength\leftmargin{0pt}
  }

\listtest{leftmargin 10pt:}{%
  %\setlength\itemsep{2ex}
  %\setlength\labelwidth{1em}
  %\setlength\labelsep{1em}
  \setlength\leftmargin{10pt}
  }

\listtest{labelwidth 10pt:}{%
  %\setlength\itemsep{2ex}
  \setlength\labelwidth{10pt}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{10pt}
  }

\listtest{labelwidth 0pt:}{%
  %\setlength\itemsep{2ex}
  \setlength\labelwidth{0pt}
  %\setlength\labelsep{1em}
  %\setlength\leftmargin{10pt}
  }


\bigskip
\bigskip


Test 1:
\begin{list}{\arabic{mycounter}.}%
  {\usecounter{mycounter}
   \setlength\itemsep{2ex}
   \setlength\labelwidth{1em}
   \setlength\labelsep{1em}
   \setlength\leftmargin{0pt}}
  \item \lipsum[1][1-2]
  \item \lipsum[2][1-2]
  \item \lipsum[3][1-2]
\end{list}



\listtest{Foo}{%
  \setlength\itemsep{2ex}
  \setlength\labelwidth{1em}
  \setlength\labelsep{1em}
  \setlength\leftmargin{0pt}
  }




\GenericWarning{Success:}{Success!!!}  % Used by `M-x cv'

\end{document}

% Local Variables:
% coding: utf-8-unix
% ee-tla: "lis"
% End: