diff --git a/README.md b/README.md
index 31ffd47..0d6b32a 100644
--- a/README.md
+++ b/README.md
@@ -255,6 +255,13 @@ npm install @abap2ui5/node-runtime express
 node --input-type=module -e 'import { serve } from "@abap2ui5/node-runtime"; await serve({ port: 3000 });'
 ```
 
+Either way, `ui5 serve` serves only the libraries `framework.libraries`
+in the example's `ui5.yaml` names: the ones the ABAP views of the embedded
+apps use, and `sap.ui.codeeditor` for abap2UI5's developer tools
+(Ctrl+F12). A library missing there fails in the browser console with a
+script load error; an app deployed to a system has every library of that
+system.
+
 The Fiori elements apps and the card need abap2UI5 1.146.0 or later. The
 READMEs of
 [`freestyle/`](https://github.com/abap2UI5/samples-embed-control/blob/standard/freestyle/README.md),
diff --git a/card/ui5-local.yaml b/card/ui5-local.yaml
index 7452bdf..1d91421 100644
--- a/card/ui5-local.yaml
+++ b/card/ui5-local.yaml
@@ -12,12 +12,15 @@ framework:
   # Zone the host brings its own SAPUI5. The embedded abap2UI5 apps load
   # whatever library their ABAP view names - the hello world app uses
   # sap.ui.layout (SimpleForm). List every library your ABAP apps use.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.f
     - name: sap.ui.integration
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 builder:
   resources:
diff --git a/card/ui5.yaml b/card/ui5.yaml
index 62a95e0..adafeb1 100644
--- a/card/ui5.yaml
+++ b/card/ui5.yaml
@@ -9,12 +9,15 @@ framework:
   # Zone the host brings its own SAPUI5. The embedded abap2UI5 apps load
   # whatever library their ABAP view names - the hello world app uses
   # sap.ui.layout (SimpleForm). List every library your ABAP apps use.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.f
     - name: sap.ui.integration
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 builder:
   resources:
diff --git a/fiori-elements-v2/ui5-local.yaml b/fiori-elements-v2/ui5-local.yaml
index bb74430..df13529 100644
--- a/fiori-elements-v2/ui5-local.yaml
+++ b/fiori-elements-v2/ui5-local.yaml
@@ -13,11 +13,14 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones the Fiori elements app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.suite.ui.generic.template
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when
diff --git a/fiori-elements-v2/ui5.yaml b/fiori-elements-v2/ui5.yaml
index 50daa6a..f413c2b 100644
--- a/fiori-elements-v2/ui5.yaml
+++ b/fiori-elements-v2/ui5.yaml
@@ -10,11 +10,14 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones the Fiori elements app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.suite.ui.generic.template
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when
diff --git a/fiori-elements/ui5-local.yaml b/fiori-elements/ui5-local.yaml
index 60f406a..c964567 100644
--- a/fiori-elements/ui5-local.yaml
+++ b/fiori-elements/ui5-local.yaml
@@ -12,11 +12,14 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones the Fiori elements app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.fe.templates
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when
diff --git a/fiori-elements/ui5.yaml b/fiori-elements/ui5.yaml
index 26c39f5..73f64cb 100644
--- a/fiori-elements/ui5.yaml
+++ b/fiori-elements/ui5.yaml
@@ -9,11 +9,14 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones the Fiori elements app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.fe.templates
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when
diff --git a/freestyle/README.md b/freestyle/README.md
index dfcec1b..360051e 100644
--- a/freestyle/README.md
+++ b/freestyle/README.md
@@ -55,6 +55,11 @@ abap2UI5's CSRF check compares the browser's `Origin` with it - nothing else
 is needed. An installation that switched `check_trust_forwarded_host` off in
 its user exit answers 403 through the proxy.
 
+`ui5 serve` serves only the libraries `framework.libraries` in `ui5.yaml`
+names: the ones the ABAP views of the embedded apps use, and
+`sap.ui.codeeditor` for abap2UI5's developer tools (Ctrl+F12). A library
+missing there fails in the browser console with a script load error.
+
 `npm run build` writes the app to deploy into `dist/`, the control in
 `dist/thirdparty/z2ui5/embed/`.
 
diff --git a/freestyle/ui5-1.71.yaml b/freestyle/ui5-1.71.yaml
index 9b01f0a..bbc54e1 100644
--- a/freestyle/ui5-1.71.yaml
+++ b/freestyle/ui5-1.71.yaml
@@ -13,6 +13,7 @@ framework:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_fiori_3
 server:
   customMiddleware:
diff --git a/freestyle/ui5-local.yaml b/freestyle/ui5-local.yaml
index 65b370b..bac4d7e 100644
--- a/freestyle/ui5-local.yaml
+++ b/freestyle/ui5-local.yaml
@@ -11,10 +11,13 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones this host app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when
diff --git a/freestyle/ui5.yaml b/freestyle/ui5.yaml
index a093b3a..23d87bb 100644
--- a/freestyle/ui5.yaml
+++ b/freestyle/ui5.yaml
@@ -8,10 +8,13 @@ framework:
   # The embedded abap2UI5 apps load whatever library their ABAP view names -
   # the hello world app uses sap.ui.layout (SimpleForm). List every library
   # your ABAP apps use, not only the ones this host app uses itself.
+  # abap2UI5's developer tools (Ctrl+F12 in an embedded app) need
+  # sap.ui.codeeditor - without it `ui5 serve` answers them with a 404.
   libraries:
     - name: sap.m
     - name: sap.ui.core
     - name: sap.ui.layout
+    - name: sap.ui.codeeditor
     - name: themelib_sap_horizon
 # The control comes from npm like any dependency; `ui5 serve` serves it
 # anyway, `ui5 build` copies it into dist/thirdparty/z2ui5/embed/ only when