The explanation is identical for two pipeline chain operators

[LaurentDardenne]

With :

dir||Cls ; dir&&Cls

Result :

According to this documentation :
The && operator executes the right-hand pipeline, if the left-hand pipeline succeeded.
Conversely, the || operator executes the right-hand pipeline if the left-hand pipeline failed.

[Jawz84]

A great catch! This can be fixed here:

explainpowershell/explainpowershell.analysisservice/AstVisitorExplainer.cs

Lines 1181 to 1194 in 9b2a344

	public override AstVisitAction VisitPipelineChain(PipelineChainAst statementChain)
	{
	var operatorString = statementChain.Operator.ToString() == "AndAnd" ? "&&" : "||";
	explanations.Add(new Explanation()
	{
	Description = $"The '{operatorString}' operator executes the right-hand pipeline, if the left-hand pipeline succeeded.",
	CommandName = "Pipeline chain",
	HelpResult = HelpTableQuery("about_Pipeline_Chain_Operators"),
	TextToHighlight = operatorString
	}.AddDefaults(statementChain, explanations));
	return base.VisitPipelineChain(statementChain);
	}

If you like, you are more than welcome to provide a pull request for this.