MS Graph REST API checkout user - rest

Question

I've managed to successfully checkout a file using the https://graph.microsoft.com/beta/drives/{driveId}/items/{itemId}/checkout
Now, I'd like to get the information about the user, who actually perform the checkout operation.
It's possible to check if the item is locked:
https://graph.microsoft.com/beta/drives/{driveId}/items/{itemId}?select=*,publication
However, according to DOCs, publication doesn't provide information about the checked user. Without information who locked the file is the whole checkin/checkout logic is useless.

Answer 1

This kind of information could be retrieved via the metadata for an item in a list as demonstrated below:
https://graph.microsoft.com/beta/sites/{site-id}/lists/{list-id}/items/{item-id}?expand=fields(select=CheckoutUserLookupId)
Once you get checkout user id (CheckoutUserLookupId field) , user details could be determined via the following endpoint:
https://graph.microsoft.com/v1.0/sites/{site-id}/lists('User Information List')/items/{CheckoutUserLookupId}
where CheckoutUserLookupId is the user id from the previous request

Answer 2

https://graph.microsoft.com/beta/sites/{site-id}/lists/{list-id}/items/{item-id} can't work with folders.
Anyway, drive endpoint "Allows access to the list as a drive" (according to MS Graph Docs). It works with folders as expected.
So I have
get the drive-id: /sites/${siteId}/drives
list root folder: /drives/{drive-id}/items/root/children?select=name,publication
if an item is locked, it's possible to list the activity on the item:
/drives/${idObj.driveId}/items/${idObj.fileId}?select=id&expand=activities
return list of actions:
"activities": [
{
"#odata.type": "#oneDrive.activityEntity",
"#odata.id": "https://xxxxxxxxxx/v2.0/oneDrive.activityEntity2a3649d6-2xxxxx",
"#odata.editLink": "oneDrive.activityEntity2a3649d6xxxxxx",
"#sharePoint.localizedRelativeTime": "0|July 30",
"action": {
"checkout": {}
},
"actor": {
"user": {
"email": "XXX#XXX",
"displayName": "vladimir",
"self": {},
"userPrincipalName": "XXX#XXX
}
},
"id": "XXXXXXXXXXXXXX",
"times": {
"recordedTime": "2018-07-31T04:59:03Z"
}
},
although no user ID at least a have the email....