Accounts Receivable and Accounts Payable are 'linked' to sub-ledgers, which means they're locked together with the sub-ledger.   All entries have to be made into a Sales Invoice or Sales Receipt.

Under 'related historical accounts', if you had a series of different account numbers in different fiscal years for Accounts Receivable (which would be a very rare thing), it would show what those prior fiscal years' account numbers were.   The purpose of that is for comparison reports, so that equivalent, but different accounts from different fiscal years, can be shown side-by-side.

Accounts Receivable and Accounts Payable are 'linked' to sub-ledgers, which means they're locked together with the sub-ledger.   All entries have to be made into a Sales Invoice or Sales Receipt.

Under 'related historical accounts', if you had a series of different account numbers in different fiscal years for Accounts Receivable (which would be a very rare thing), it would show what those prior fiscal years' account numbers were.   The purpose of that is for comparison reports, so that equivalent, but different accounts from different fiscal years, can be shown side-by-side.