Field reomval in a sales order for a line item in additional tab B

Hello Folks,

In a sales order for a line item in additional tab B, one custom field has been added. I need to remove that field.

When I check F1 help  for this field, i could only see is table and data element name, no filed name.

I tried to search using field screen name  in VBAP table also but could not find any thing.

Any clue, how can I find details of thsi field.

Thanks