A profile with most (vanilla) hardening options enabled by default, potentially at the cost of stability, features and performance. This includes a hardened kernel, and limiting the system information available to processes through the /sys and /proc filesystems. It also disables the User Namespaces feature of the kernel, which stops Nix from being able to build anything (this particular setting can be overriden via ). See the profile source for further detail on which settings are altered. This profile enables options that are known to affect system stability. If you experience any stability issues when using the profile, try disabling it. If you report an issue and use this profile, always mention that you do.