Even when the binaries are signed you'd still have to trust Tailscale they didn't modify the code before compilation, maybe putting in a simple back door. They

Even when the binaries are signed you'd still have to trust Tailscale they didn't modify the code before compilation, maybe putting in a simple back door. They probably don't, but you can't really know. When you have binary reproducible builds such a thing would immediately be obvious and hell would break loose if they attempted it.