Here are some examples and a good description of the ActiveDirectory ACL:
Script example to compare ActiveDirectory OU ACL ( Security Groups )
by J.Kühnis 25.11.2019
Import-Module ActiveDirectory
$OU1 = Get-ACl -Path 'AD:\OU=Sales,OU=UserAccounts,DC=FABRIKAM,DC=COM' | Select-Object -ExpandProperty Access | select IdentityReference
$OU2 = Get-ACl -Path 'AD:\OU=Marketing,OU=UserAccounts,DC=FABRIKAM,DC=COM' | Select-Object -ExpandProperty Access | select IdentityReference
Compare-Object $OU1 $OU2 -IncludeEqual