tcolorbox 0pt wide lines visible in some PDF viewers

Use the enhanced jigsaw option. This improves the line drawing/suppression and the hidden frame parts are not visible in Acrobat, evince and FireFox preview.

This does not mean, that there aren't any lines visible in other PDF viewers. I can't check for others.

\documentclass{article}

\usepackage[most]{tcolorbox}


\usepackage{blindtext}

\begin{document}

\begin{tcolorbox}[
  enhanced jigsaw,
    breakable=true,
    outer arc=0pt,
    arc=0pt,
    colback=white,
    rightrule=0pt,
    leftrule=2pt,
    toprule=0pt,
    top=0pt,
    right=-3pt,
    bottom=0pt,
    bottomrule=0pt,
    colframe=black,
    enlarge left by=15pt,
    width=\linewidth - 15pt]
\blindtext

\end{tcolorbox}

\end{document}

Christian Hupfer already gave an answer with the enhanced jigsaw option which is always preferable, if the box has some 0pt lines.

For your special application, you can use empty as an alternative. This skin simply draws nothing. The black rule can be added by borderline west. This way, there should be no ghost line with any previewer.

\documentclass{article}

\usepackage[most]{tcolorbox}


\usepackage{blindtext}

\begin{document}

\begin{tcolorbox}[
    empty,
    breakable=true,
    outer arc=0pt,
    arc=0pt,
    % colback=white,
    rightrule=0pt,
    leftrule=2pt,
    borderline west={2pt}{0pt}{black},
    toprule=0pt,
    top=0pt,
    right=-3pt,
    bottom=0pt,
    bottomrule=0pt,
    % colframe=black,
    enlarge left by=15pt,
    width=\linewidth - 15pt]
\blindtext

\end{tcolorbox}

\end{document}