This bug came up in the
MDEV-15132 testing. When InnoDB has completed the rollback of a recovered transaction, it used to display the transaction identifier. Starting with the change bug#16845421 INNODB: CRASH WHILE RECOVERING A TRANSACTION in MySQL 5.7.2 (and the merge of MySQL 5.7.9 to MariaDB 10.2.2) it would always display 0 instead:
The reason is that the trx->id would be reset at transaction commit.