I've found your snippets to be very helpful to move my project along. Right now I'm stuck on getting extensions attributes on a group. I realize you demonstrate openextensions, but I would prefer in this case to use schemeextensions or extensionproperties. The example below doesn't work when copying and pasting into graph explorer, I also couldn't get this to work via code. Received an access denied in both cases however I do have Directory.AccessAsUser.All.
"odata.metadata": "https://graph.windows.net/mydomain/$metadata#directoryObjects/Microsoft.DirectoryServices.ExtensionProperty",
"value": [
{
"odata.type": "Microsoft.DirectoryServices.ExtensionProperty",
"objectType": "ExtensionProperty",
"objectId": "bd4cdaa3-3e9c-41a2-8308-8c10403c3989",
"deletionTimestamp": null,
"appDisplayName": "",
"name": "extension_67183a58655d4977acd8a4815cbff2cd_SecondaryOwners",
"dataType": "String",
"isSyncedFromOnPremises": false,
"targetObjects": [
"Group"
]
},`