What is"ContentHash" exactly in Azure?

## Description
I found some components have **ContentHash** property, but I don't know what exactly is.

Let's take **Integration Account Map** as an example. I want to compare content between local map file and map file in integration account via its hash(the content are the same).

I get the map by **`Get-AzIntegrationAccountMap`**(https://docs.microsoft.com/en-us/powershell/module/az.logicapp/get-azintegrationaccountmap), I found the map file in integration account has "ContentHash" property. but it's something I can't understand.

## Steps to reproduce

The ContentHash propery seems neither **MD5** format hash nor **re-base64** string of MD5 hash

$map = Get-AzIntegrationAccountMap -ResourceGroupName XXX -Name XXX -MapName XXX

$map.ContentLink.ContentHash


Algorithm Value                   

--------- -----                   

md5       5I0T8qRvRw32Fgc+e7LocA==

$mapFile = "c:\map.xml"

$hashNew = Get-FileHash -Path $mapFile -Algorithm MD5

$hashNew | select  Algorithm, Hash


Algorithm Hash                            

--------- ----                            

MD5       E48D13F2A46F470DF616073E7BB2E870