diff --git a/crates/webui/src/components/component_detail.rs b/crates/webui/src/components/component_detail.rs
index 88899da..e90a0d4 100644
--- a/crates/webui/src/components/component_detail.rs
+++ b/crates/webui/src/components/component_detail.rs
@@ -184,11 +184,16 @@ fn component_file_sources(files: &[ComponentFileRef]) -> Vec<SourceView> {
                 return None;
             }
             let file = &file_ref.file;
+            let content = if role == ComponentFileRole::WasmComponent {
+                SourceContent::Binary
+            } else {
+                SourceContent::FetchFile {
+                    digest: file.digest.clone(),
+                }
+            };
             Some(SourceView {
                 file_name: file.path.clone(),
-                content: SourceContent::FetchFile {
-                    digest: file.digest.clone(),
-                },
+                content,
                 metadata: Some(SourceMetadata {
                     role: component_file_role_label(role),
                     entrypoint: role == ComponentFileRole::JsEntrypoint,
@@ -269,6 +274,7 @@ pub fn component_detail(
     let wit_state = use_state(|| None);
     let wit_loaded = use_state(|| false);
     let selected_tab = use_state(|| ComponentDetailTab::Exports);
+    let show_extensions = use_state(|| false);
     let deployment_config = use_state(|| None::<Result<Option<ComponentDeploymentConfig>, String>>);
 
     // Fetch raw WIT only when its tab is selected.
@@ -390,7 +396,18 @@ pub fn component_detail(
         }
     });
 
-    let exports = map_interfaces_to_fn_details(component.exported_fns(), InterfaceFilter::All);
+    let has_extensions = component
+        .exported_fns()
+        .iter()
+        .any(|fn_detail| fn_detail.ffqn.ifc_fqn.is_extension());
+    let exports = map_interfaces_to_fn_details(
+        component.exported_fns(),
+        if *show_extensions {
+            InterfaceFilter::All
+        } else {
+            InterfaceFilter::WithoutExtensions
+        },
+    );
     let render_exported_ifc_with_fns =
         |ifc_fqn: &IfcFqnName, fn_details: &[FunctionMetadataLite]| {
             let exported_fn_details = fn_details
@@ -433,15 +450,32 @@ pub fn component_detail(
         .iter()
         .map(|(ifc_fqn, fn_details)| render_exported_ifc_with_fns(ifc_fqn, fn_details))
         .collect::<Vec<_>>();
-    let exported_functions = if exported_ifcs_fns.is_empty() {
-        html! {
+    let on_show_extensions_change = {
+        let show_extensions = show_extensions.clone();
+        Callback::from(move |e: Event| {
+            let input: web_sys::HtmlInputElement = e.target_unchecked_into();
+            show_extensions.set(input.checked());
+        })
+    };
+    let exported_functions = html! { <>
+        if has_extensions {
+            <label class="component-show-extensions">
+                <input
+                    type="checkbox"
+                    checked={*show_extensions}
+                    onchange={on_show_extensions_change}
+                />
+                {" Show extension functions"}
+            </label>
+        }
+        if exported_ifcs_fns.is_empty() {
             <p class="component-empty-state">
                 {"This component does not export any functions."}
             </p>
+        } else {
+            { for exported_ifcs_fns }
         }
-    } else {
-        html! { <>{ for exported_ifcs_fns }</> }
-    };
+    </> };
 
     let dependencies = || {
         let connections = component_connections(component, deployment_components);
diff --git a/crates/webui/src/components/deployment_config_view.rs b/crates/webui/src/components/deployment_config_view.rs
index e0e6df0..165a61f 100644
--- a/crates/webui/src/components/deployment_config_view.rs
+++ b/crates/webui/src/components/deployment_config_view.rs
@@ -78,6 +78,8 @@ pub enum SourceContent {
     Fetch {
         file: String,
     },
+    /// A binary file such as a WASM component, listed but not displayable.
+    Binary,
 }
 
 const SOURCE_MARKER: &str = "(source rendered below)";
@@ -224,7 +226,10 @@ pub fn build_sections_from_manifest(manifest: &Value, files: &[FileRefSer]) -> V
         let Some(tables) = manifest.get(toml_key).and_then(Value::as_array) else {
             continue;
         };
-        let has_backtrace = matches!(*toml_key, "workflow_wasm" | "webhook_endpoint_wasm");
+        let has_backtrace = matches!(
+            *toml_key,
+            "activity_wasm" | "workflow_wasm" | "webhook_endpoint_wasm"
+        );
         let has_script = matches!(
             *toml_key,
             "workflow_js" | "activity_js" | "activity_exec" | "webhook_endpoint_js"
@@ -432,7 +437,9 @@ pub fn collapsible_source(
                     .as_ref()
                     .and_then(|result| result.as_ref().as_ref().ok())
                     .cloned(),
-                SourceContent::Oci { .. } | SourceContent::ExternalPath { .. } => None,
+                SourceContent::Oci { .. }
+                | SourceContent::ExternalPath { .. }
+                | SourceContent::Binary => None,
             }?;
             let language = PathBuf::from(&source.file_name)
                 .extension()
@@ -444,11 +451,20 @@ pub fn collapsible_source(
         },
     );
 
+    if source.content == SourceContent::Binary {
+        return html! {
+            <div class="source-block source-block-binary">
+                <div class="source-summary">{ source_summary_contents(source) }</div>
+            </div>
+        };
+    }
+
     let body = if !*opened {
         html! {}
     } else {
         let source_available = match &source.content {
             SourceContent::Inline(_) => true,
+            SourceContent::Binary => unreachable!("binary sources return early"),
             SourceContent::Oci { image } => {
                 return html! {
                     <details {ontoggle} class="source-block">
@@ -518,16 +534,22 @@ fn source_summary(source: &SourceView) -> Html {
         .is_some_and(|metadata| metadata.entrypoint);
     html! {
         <summary class={classes!(entrypoint.then_some("entrypoint"))}>
-            <span class="source-file-name">{ &source.file_name }</span>
-            if let Some(metadata) = &source.metadata {
-                <span class="source-file-metadata">
-                    <span class="source-file-role">{metadata.role}</span>
-                </span>
-            }
+            { source_summary_contents(source) }
         </summary>
     }
 }
 
+fn source_summary_contents(source: &SourceView) -> Html {
+    html! { <>
+        <span class="source-file-name">{ &source.file_name }</span>
+        if let Some(metadata) = &source.metadata {
+            <span class="source-file-metadata">
+                <span class="source-file-role">{metadata.role}</span>
+            </span>
+        }
+    </> }
+}
+
 #[derive(Properties, PartialEq)]
 pub struct DeploymentConfigViewProps {
     pub sections: Vec<SectionView>,
diff --git a/crates/webui/src/components/deployment_diff_page.rs b/crates/webui/src/components/deployment_diff_page.rs
index f72ce11..e7d6faa 100644
--- a/crates/webui/src/components/deployment_diff_page.rs
+++ b/crates/webui/src/components/deployment_diff_page.rs
@@ -430,6 +430,7 @@ async fn resolve_source(source: SourceView, component_id: Option<ComponentId>) -
         SourceContent::ExternalPath { path } => ResolvedSource::Note(format!(
             "Source is read at runtime from the external path `{path}`."
         )),
+        SourceContent::Binary => ResolvedSource::Note("Binary file, not shown.".to_string()),
         SourceContent::FetchFile { digest } => rest::deployments::file(&digest)
             .await
             .map(ResolvedSource::Text)
diff --git a/crates/webui/styles/pages/_definitions.scss b/crates/webui/styles/pages/_definitions.scss
index 490ea52..718a018 100644
--- a/crates/webui/styles/pages/_definitions.scss
+++ b/crates/webui/styles/pages/_definitions.scss
@@ -96,7 +96,8 @@
   border-radius: $border-radius-lg;
   background: $color-bg-primary;
 
-  > summary {
+  > summary,
+  > .source-summary {
     display: flex;
     align-items: center;
     gap: $spacing-sm;
@@ -130,6 +131,18 @@
     }
   }
 
+  > .source-summary {
+    cursor: default;
+
+    &::before {
+      visibility: hidden;
+    }
+
+    &:hover {
+      background: $color-bg-secondary;
+    }
+  }
+
   &[open] {
     > summary {
       border-bottom: 1px solid $color-border-primary;
diff --git a/crates/webui/styles/pages/_deployment.scss b/crates/webui/styles/pages/_deployment.scss
index 5d65df5..c7fde3b 100644
--- a/crates/webui/styles/pages/_deployment.scss
+++ b/crates/webui/styles/pages/_deployment.scss
@@ -303,6 +303,13 @@
 
     .component-detail-tabs { margin-top: $spacing-sm; }
     .component-detail-tab-content { min-height: 0; }
+
+    .component-show-extensions {
+        display: inline-flex;
+        align-items: center;
+        gap: $spacing-xs;
+        margin: $spacing-sm 0;
+    }
 }
 
 .deployment-component-search {