[Maria-developers] a mysterious (to me) block of code in the middle of ha_recover

Hello, The ha_recover function in MySQL 5.5.28 has a block of code in the middle of it labelled with WILL_BE_DELETED_LATER that gets compiled into mysqld. The ha_recover function in Mariadb 5.5.28a does not have this code in it. It appears that the code forces prepared transactions to be rolled back in MySQL. Does anyone know what this code does? Does anyone know why this code exists in MySQL but not in Mariadb? Thanks Rich Prohaska