Whether the initrd can be built even though modules listed in boot.initrd.kernelModules or boot.initrd.availableKernelModules are missing from the kernel. This is useful when combining configurations that include a lot of modules, such as hardware.enableAllHardware, with kernels that don't provide as many modules as typical NixOS kernels.
Note that enabling this is discouraged. Instead, try disabling individual modules by setting e.g. boot.initrd.availableKernelModules.foo = lib.mkForce false;