After I install a CU I go through my registry to see what the CU has reset.
I've often seen **del.<keyname> and **delvals. but haven't been able to find out what they mean. Google seems oddly devoid of any information on these.

What are they?

It's become a concern now because I see values I have set now bee converted to **.del. For example, I had disabled cloud search (AllowCloudSearch via group policy). The registry key was set to 0 and was a dword. It's now a string **del.allowcloudsearch.

As I was scanning the registry I came across literally dozens of these. Since my installation is tweaked via setupcomplete.cmd, are some of my tweaks now redundant. If Microsoft is changing these keys is it because they are no longer used, or are they being malicious and deciding what they want my settings to be? And I therefore need to re-apply those settings after each CU?