diff --git a/TODO.org b/TODO.org
index f9fc4f1d..40382148 100644
--- a/TODO.org
+++ b/TODO.org
@@ -1274,7 +1274,8 @@ No ordering of the frees fixes it: the container holds a pointer to the header.
 =arena-destroy= now frees the pages and the arena record and retires the
 allocator header — epoch bumped, procedure trapping as =DestroyedAllocator=,
 never freed — so the stale check reads live memory on every side that makes it.
-Rules out freeing the header while any container may hold it. See
+Rules out freeing the header while any container may hold it. The
+=DestroyedAllocator= trap prints no site: the allocator procedure is given none. See
 docs/BUILT.md, "Three amendments to a frozen spec".
 
 ** DONE Map removal costs a backward-shift loop