run 23

docs/pt2-protocol-summary.md

@@ -241,6 +241,7 @@ confirmed Sony definition.
 | `07 C0 7A 50 A6 11` | exact echo of `07 80 E8 40 30 45`, seen once | low | new structured response family on the `E8` branch; not yet repeated |
 | `07 80 7A 50 26 D1` | host-shaped `E8` branch, reproduced across HE8-HE11 group 1 | medium-high | reproducible downstream response family in the `E8` / `FA` / `7A` branch |
 | `07 80 7A 28 D3 5C` | host-shaped `E9` neighbor, group 1 | low-medium | nearby distinct `7A`-family response; suggests an `E8`/`E9` selector neighborhood |
+| `07 80 7B 50 26 D0` | host-shaped `EC` neighbor, group 1 | low-medium | new sibling family suggesting the `Ex` region is a selector-like strip |
 
 Current caution:
 
@@ -264,6 +265,13 @@ Current caution:
 - Nearby host-shaped neighbors are mixed rather than uniform:
   `E9` produced a distinct `7A`-family response, while `E7` and `EA` steered
   back toward known heartbeat-family transients.
+- The `E9` sibling behaves like `E8` structurally:
+  exact and host-shaped handling of `07 80 7A 28 D3 5C` did not advance the
+  exchange, so the active control point still appears to be the `Ex` selector
+  step rather than the downstream `7A` reply.
+- Extending outward reinforced the selector-strip model:
+  `E6` and `EB` fall into the `07 80 40 40 30 ED` transient family, while `EC`
+  opens a new `07 80 7B 50 26 D0` sibling response.
 
 ## What We Know
 
@@ -290,6 +298,12 @@ Current caution:
   response branch.
 - `E8` is not completely isolated: nearby `E9` can also open a `7A`-family
   response, but with different payload bytes.
+- The emerging pattern is that `E8` and `E9` may be sibling selector-like host
+  entries into related status/response families, while `E7` and `EA` bias back
+  toward heartbeat-family transients.
+- The wider `Ex` region now looks like a mixed selector surface:
+  some values collapse into heartbeat-family transients, while others open
+  related `7A` / `7B` downstream families.
 
 ## What We Do Not Know