Content Editor Webpart is missing in SharePoint online

Fix using powershell

Connect-SPOService -Url https://abc-admin.sharepoint.com 

set-SPOsite https://abc.sharepoint.com -DenyAddAndCustomizePages 0 

How to Connect to SharePoint Online from PowerShell

 Connect-SPOService -Url https://YourTenant-admin.sharepoint.com

Download all wsp files from Central Admin using Powershell

$pathName = "c:\WSPFiles\"

foreach ($solution in Get-SPSolution)

   {

 

  

    $title = $Solution.Name

    $filename = $Solution.SolutionFile.Name

    $solution.SolutionFile.SaveAs("$pathName\$filename")

}

Customize the Quick Launch as Expand/Collapse in SharePoint 2013/2016 Using Code

var quickLaunchLinks = $("div[id$='QuickLaunchMenu'] > ul > li:has('ul') > a");

quickLaunchLinks.prepend("<span class='ms-commentexpand-iconouter ql-icon'>

<img alt='expand' src='/Comm/Comms2/_themes/1/spcommon-B35BB0A9.themedpng?ctag=2' class='ms-commentexpand-icon'></span>");

quickLaunchLinks.closest("li").find("> ul").hide();

quickLaunchLinks.click(function(e) {

    e.preventDefault();

    var childUl = $(this).closest("li").find("> ul");

    var visibleChildUL = childUl.is(":visible")

    if (visibleChildUL) {

        $(this).find(".ql-icon").replaceWith("<span class='ms-commentexpand-iconouter ql-icon'>

<img alt='Expand' src='/Comm/Comms2/_themes/1/spcommon-B35BB0A9.themedpng?ctag=2' class='ms-commentexpand-icon'></span>");

        childUl.slideUp();

    } else {

        $(this).find(".ql-icon").replaceWith("<span class='ms-commentcollapse-iconouter ql-icon'>

<img alt='Collapse' src='/Comm/Comms2/_themes/1/spcommon-B35BB0A9.themedpng?ctag=2' class='ms-commentcollapse-icon'></span>");

        childUl.slideDown();

    }

});