diff --git a/crates/helm-core/src/expected.rs b/crates/helm-core/src/expected.rs
index 8b58728..5d5f5a8 100644
--- a/crates/helm-core/src/expected.rs
+++ b/crates/helm-core/src/expected.rs
@@ -27,6 +27,17 @@
 //!
 //! It is a best case, deliberately. A real to-hit number depends on two
 //! machines, a map and a turn, none of which a library has.
+//!
+//! Heat is not in it either, and that is a division rather than an oversight:
+//! `CombatMetrics::heat_efficiency` is a column of its own, so "hits hard and
+//! can keep doing it" is a filter with two terms in it rather than one figure
+//! that has quietly made up its mind.
+//!
+//! Nor is whether a launcher has anything to fire. [`crate::damage_at_range`]
+//! checks, because the formation rules it serves are defined that way; this
+//! does not, because seven designs in the library declare a field gun and no
+//! bin for it, and a machine whose paperwork is short a magazine is not a
+//! machine that cannot shoot.
 
 use crate::{Catalogue, EquipmentEntry, Unit};