This is not a conversation about guns. This is a conversation about items that have withstood abuse that are near unbreakable.
Some items I have heard referenced as AK47 of:
Gerber MP600: It’s a multi tool
Old Thinkpad Laptops
Mag lights
Toyota Hilux
Open source is good because it means it can be maintained even if the manufacturer shuts down. One of the biggest issues with keeping older tech alive and in a useful state is proprietary firmware.