The top half of the xls shows the fields that compare one-to-one between 7.5 and 8.8, with the left-hand column being 7.5 and the right-hand being 8.8. Field lengths may be different, but the field is the same field.
The lower portion of the left-hand column shows the fields that are no longer present on that table in 8.8, with the lower right-hand column showing fields that are new for that table in 8.8.
Tables that have been renamed or replaced are noted within the compare. Ledger amounts are stored differently in 8.8, and those differences are also noted.