Trust list is your personal view of the trust system. Imo, trust feedbacks are suggestions from others on who is trustworthy or rational and who isn't. With your custom trust list, you choose whose opinion is shown to you and whose isn't, based on your assessment of the members judgement
Overview:
Go to your trust settings
To add a member to your trust list, enter their name into the box shown. Their feedback would be visible to you.
To exclude a member enter their name with the prefix ~. For example, ~qwerty. Their feedback would not be visible to you.

If you do not have a trust list, you would only see feedback from DT - default trust members.