See also bug 40352. It needs:

• field: rb.rd_interwiki
  1. for the 3rd link in the chain in the output

• conds: (ra.rd_interwiki = NULL OR ra.rd_interwiki = "")
  1. to exclude redirects where the second item is interwiki, since those can't
  2. be double redirects

Version: unspecified
Severity: major