The existence of this is fascinating and horrifying at the same time. I wonder how he tests it though; when writing tons of YAML for K8s or Ansible, you usually test it in a test environment before putting it in production. Unlike the other cases though, a bug in your YAML here can literally lead people to lose their lives.
The actual horrifying part is that this is more of a coping tool than a warning system, as its utility as the latter is limited even in Kyiv. If you are not at the point of accepting your fate, but have already given up on attempting to get to actual shelter, you can set this up and only hide from glass shrapnel for an hour when the cruise missiles and killer drones arrive instead of hiding for hours while they fly all over the country through the gaps of air defense.
For anywhere closer to the frontline than Kyiv this is almost completely useless. Travel time of even non-hypersonic ballistics, hell, even of glide bombs is so short you'd be listening to your alarm and the sound of explosions almost simultaneously.