diff --git a/docs/v4.0.0/ENGINE.md b/docs/v4.0.0/ENGINE.md
index 3b7cf3ab..ed3af66a 100644
--- a/docs/v4.0.0/ENGINE.md
+++ b/docs/v4.0.0/ENGINE.md
@@ -192,8 +192,13 @@ program with the node as its interpreter. That is withdrawn. From here:
   hosted builds agree with each other; the three bare-metal builds agree
   with each other.
 
-What the two still share, if anything beyond the engine in `v4/src`, is
-for Captain Bob to say.
+**What the two share (confirmed by Captain Bob the same day, "yes,
+exactly"):** the engine in `v4/src`; the FORTH-79 capsule,
+`capsules/v4/forth79.4th`; and its POST, `capsules/v4/post79.4th`. **The
+nuclei are separate.** The bare-metal nucleus needs word IDs in its
+headers and words that are called where the hosted one compiles them in
+line; the hosted nucleus need not have either. The hosted product may
+become a hosted version of an SDK.
 
 **Two things in v3's C words do not carry over as they are**, and must be
 dealt with word by word: