Icons automatically pinned to taskbar after every reboot in Windows 10

From this documentation: https://docs.microsoft.com/en-us/windows/configuration/configure-windows-10-taskbar

In my case I find: C:\Users\Default\AppData\Local\Microsoft\Windows\Shell\LayoutModification.xml

here i have this line: CustomTaskbarLayoutCollection PinListPlacement="Replace"

-> the items in this PinList will be pinned to the taskbar on every logon (through explorer.exe as far I understand). Even if I remove the items and logon again with same profile the items will be pinned aside manually pinned items.

The part of the xml that defines the StartMenu will only apply on first logon.

There are a few different ways administrators can accomplish this; the two most common are likely via GPO settings or through a layout modification XML file pushed through GPO.

The local group policy editor has a Start Menu and Taskbar section within User Configuration that has all kinds of options:

You can get really into specifics through the XML method, with a file that looks like this:

<?xml version="1.0" encoding="utf-8"?>
<LayoutModificationTemplate
    xmlns="http://schemas.microsoft.com/Start/2014/LayoutModification"
    xmlns:defaultlayout="http://schemas.microsoft.com/Start/2014/FullDefaultLayout"
    xmlns:start="http://schemas.microsoft.com/Start/2014/StartLayout"
    xmlns:taskbar="http://schemas.microsoft.com/Start/2014/TaskbarLayout"
    Version="1">
  <CustomTaskbarLayoutCollection>
    <defaultlayout:TaskbarLayout>
      <taskbar:TaskbarPinList>
        <taskbar:UWA AppUserModelID="Microsoft.MicrosoftEdge_8wekyb3d8bbwe!MicrosoftEdge" />
        <taskbar:DesktopApp DesktopApplicationLinkPath="%APPDATA%\Microsoft\Windows\Start Menu\Programs\System Tools\File Explorer.lnk" />
      </taskbar:TaskbarPinList>
    </defaultlayout:TaskbarLayout>
 </CustomTaskbarLayoutCollection>
</LayoutModificationTemplate>

Where you can see there is a specific section for <taskbar:TaskbarPinList>.