Reviving a Lookup field in a published 'read-only' Content Type

A Lookup field as part of a Content Type in the Content Type Hub that is published will not appear in the other Site Collections because it's missing the link to the connected List.
But it's possible to revive this Lookup field in the published 'read-only' Content Type that's added to a List or Document library.

First add a list in the Content Type Hub and add an extra Column named 'Description' to it:

Create a Site Column of the type Lookup and connect it to the List:



Create a new Content Type based on Document:

Add the Lookup field to the Content Type:

Publish the Content Type:

The Content Type is now available in the other Site Collections.

But there is no Lookup field in the published 'read-only' Content Type.

Create a similar List and Lookup field with the same name in this or other Site Collection:

Add some items to the List:

Create a Site Column of the type Lookup with the same name (and typo) and connect it to the List:

Go to a Document library and set 'Allow management of content types' to Yes in the Advanced Settings, add the published Content Type to the Library and Set as default Content Type:

Add a new document to the Library; there is no Lookup field (yet):

Now 'Add from existing site columns' the local Lookup field:

It looks like the Site Column is not added to the read-only Content Type.



And here is the magic. The Lookup field is revived and is connected to the local List.