Which code routine loads proper code on ITCM in X-CUBE-PERF-H7 package?

I am testing ITCM on STM32H735 by using X-CUBE-PERF-H7 package.

In the stm32h7x3_cpu_perf project, some codes are located to ITCM region using a scatter file.

After I download the executable code on the chip, I powered off the chip and run the code.

I presume that the code wouldn't run because ​the code located in the ITCM would disappear. However, the code runs successfully.

I try to find a routine which move some code to ITCM, but I can not find it.

How does ITCM has some code?