diff --git a/packages/lockdown/NEWS.md b/packages/lockdown/NEWS.md
new file mode 100644
index 0000000000..4762acdac5
--- /dev/null
+++ b/packages/lockdown/NEWS.md
@@ -0,0 +1,19 @@
+User-visible changes to `@endo/lockdown`:
+
+# Next release
+
+- Changed `@endo/lockdown/commit-debug.js` so that it now sets
+  the `lockdown` option `errorTaming: 'unsafe-debug'` instead of
+  just `errorTaming: 'unsafe'`. This is a further loss of safety in
+  exchange for a better development experience. For testing and debugging
+  purposes during development, this is usually the right tradeoff.
+
+  In particular,
+  `errorTaming: 'unsafe'` endangered only confidentiality, whereas
+  `errorTaming: 'unsafe-debug'` also endangers integrity, essentially by
+  directly exposing the (non-standard and dangerous) v8 `Error`
+  constructor API.
+
+  In exchange, stack traces will more often have accurate line numbers into
+  the sources of transpiled code, such as TypeScript sources. See
+  [`errorTaming` Options](https://github.com/endojs/endo/blob/master/packages/ses/docs/lockdown.md#errortaming-options) for more on these tradeoffs.
diff --git a/packages/lockdown/commit-debug.js b/packages/lockdown/commit-debug.js
index 9595aa0a94..03e02a2197 100644
--- a/packages/lockdown/commit-debug.js
+++ b/packages/lockdown/commit-debug.js
@@ -21,7 +21,7 @@ lockdown({
   // NOTE TO REVIEWERS: If you see the following line commented out,
   // this may be a development accident that should be fixed before merging.
   //
-  errorTaming: 'unsafe',
+  errorTaming: 'unsafe-debug',
 
   // The default `{stackFiltering: 'concise'}` setting usually makes for a
   // better debugging experience, by severely reducing the noisy distractions