This way is tagged as access=military. Unlike for access=private there is no built-in way that you can use to open up military roads. But this should be easy to do with some modification of the Java code. You could add a similar option (car|block_military=false) that you would implement just like block_private:
or simply unblock military when block_private=false, or even more simple just remove military from the list of restricted values altogether here:
We will try and remove it from the below, as we dont want to transverse military bases unless they are the destination. Does something like this look right?