I would love to see a cross-platform sandboxing API (to unify some subset of seccomp, AppCointainer, App Sandbox, pledge, capsicum, etc), perhaps just opportunistic/best-effort (fallback to allow on unsupported capability/platform combinations). We've seen this reinvented over and over again for isolated execution environments (Java, JS, browser extensions...), maybe this will finally trigger the push for something system-level, that any program can use.