Function in_guest_reserved_signals 

pub fn in_guest_reserved_signals(config: &DetConfig, backend: Backend) -> u64

The signals the in-guest runtime keeps for itself in a run of backend configured by config (detcore::Config::in_guest_reserved_signals), bit n - 1 for signal n, for Hermit’s default in-guest route: SIGSYS, its syscall trap, always; SIGSEGV while it subscribes instructions, when it installs its instruction-fault handler for SIGSEGV; and SIGTRAP while LiteInst’s guard router can be installed, which is site patching on (in_guest_guard_router_installed): never on in-guest-trap, whose config.in_guest_site_patching_off the caller has set first. The subscription is Detcore’s own decision from the same configuration (Tool::subscriptions), which each in-guest Tool image reads to choose its instruction subscriptions (reverie-inguest tool_install.rs:191-195). Empty (0) for every other backend. The in-guest loader route never calls this, so its set stays empty: today’s behaviour there (D13(a)).