TFS 2017 (Web Portal) - Modify Columns of Child grid on Links tab of a User Story

I'm trying to look for an option to modify the columns for child links of a user story. I want to add the "Assigned To" column to see who is/was working on this child task.

Here's the screenshot of the web screen I am asking about:

There is no built-in option/way to simply add/manage the columns in TFS user story.

However, you could use work item query as a workaround to achieve your requirement. There is a assign to column of the query result

We could use "Tree of work items" type of query:

1. Select "Tree of work items"
2. Set up the query for the top level work items, "User Story" with id 105 for example here (See below screenshot, just specify the Parent work item ID here).
3. Under "Filters for linked work items" you can exclude descendent items, or specify the Child work item types, for example only show Task and Bug, just set Work Item Type in Task,Bug, or leave it as [Any], it will returns all the types of child work items for the specific Parent.
4. Filter options : Match top-level work items first, Type of tree : Parent/Child

The result should be something as below, you could clear see the Assigned tocolumn of User Story's child task and know who is/was working on this child task.