Kernel image (vmlinuz...) on /boot has always the same date/time across different compilations. Where is it specified?

On a Fedora System, I'm often recompiling the kernel in order to add the necessary T2 patches for the kernel to benefit from the full capabilities of my MacBook Pro (and also so that the keyboard works with the apple-bce drivers). It happens though that, when I recreate the kernel package RPMs using the original SRPM from the Fedora repository, no matter when I compile the kernel, the installed vmlinuz file that goes into /boot has always the same date/time for each release (independent of the compilation date/time). This happens even for my custom kernel (in which I just stuff the patches inside linux-kernel-test.patch before compiling). The problem with this is that I endup having multiple vmlinuz... images on /boot with the exact same date/time, which confuses refind (the boot loader I use) on what image to load. Of course I workaround this by running touch after installing the custom Kernel rpms, but I'd like to know where is this date/time configured. I could not determine this by doing a quick visual inspection of the .spec file and of the the source code, and I'd really appreciate if a good soul could indicate me the spot and file. Note: I understand the date is artificially set so that the generated kernels have uniform properties for the same version and patch level, which is good for testing purposes, but this is not clear for me if this artificial date/time is a distribution independent kernel attribute or a Fedora package attribute.