It is often useful to quickly know a branch's parent branch. For example:

main
  -feat/a
    -feat/b
    -feat/c
  -feat/d

main is the parent of feat/a and feat/d. If I merge feat/d with main and I want those changes to appear in the other child branches, I can rebase feat/a on main, then rebase feat/b and feat/c on feat/a.

To determine this in Bitbucket's UI, I need to click on each branch and check each parent. It would be nice if there was a Parent column in the summary Branches view which contained this information.