UTFANSWF v23 — CANONICAL RINGDOWN / NZH TECHNICAL RECORD
Release: v23 / September 1, 2026

AUTHORITATIVE RESULT
Kerr QNM benchmark with canonical stationary R+R^2 branch
cT^2 = 1
mT^2 = 0
R_NZH = 0
Upsilon = 0
No canonical numerical axion-to-echo intertwiner is promoted.

EXECUTABLE ROW 23
Events: 4
max frequency fractional error = 0.13470288121686144
max damping-time fractional error = 0.07485203197511037
Canonical echo amplitude from Row 19 action: zero
Nonzero echo branch executed: false
Row 23 PASS does not mean an echo was detected or required.

STATUS
Internal PASS; reproduced run at Row 23 scope. Nonzero reflective-echo dynamics remain open/noncanonical.

FAILURE CONDITION
Failure to reproduce the Kerr QNM frequency/decay benchmark or canonical Row 19 GW handoff; equivalently failure to maintain R_NZH=0 and epsilon1=Upsilon=0 in the regular canonical branch. A verified nonzero echo contradicts the no-required-echo canonical branch, but does not alone kill all UTFANSWF if a source-complete dynamical NZH branch is independently derived and re-gated.

OPEN BOUNDARY
Derive source-complete reflective NZH dynamics without fitting the legacy echo holdout, satisfy rho(U_echo)<1, and independently derive any axion/echo inter-channel projection before numerical promotion.