diff --git a/packages/vscode-ext/README.md b/packages/vscode-ext/README.md
index afedd282..9d23c1e2 100644
--- a/packages/vscode-ext/README.md
+++ b/packages/vscode-ext/README.md
@@ -4,6 +4,17 @@ _[marketplace](https://marketplace.visualstudio.com/items?itemName=QURI.vscode-s
 
 This extension provides support for [Squiggle](https://www.squiggle-language.com/) in VS Code.
 
+Features:
+
+- Preview `.squiggle` files in a preview pane
+- Syntax highlighting for `.squiggle` and `.squiggleU` files
+
+# Configuration
+
+Some preview settings, e.g. whether to show the summary table or types of outputs, can be configurable on in the VS Code settings and persist between different preview sessions.
+
+Check out the full list of Squiggle settings in the main VS Code settings.
+
 # Build locally
 
 We assume you ran `yarn` at the monorepo level for all dependencies.
diff --git a/packages/vscode-ext/package.json b/packages/vscode-ext/package.json
index 2e3c50ea..db6dcfa6 100644
--- a/packages/vscode-ext/package.json
+++ b/packages/vscode-ext/package.json
@@ -33,6 +33,16 @@
           "Squiggle"
         ],
         "configuration": "./language-configuration.json"
+      },
+      {
+        "id": "squiggleU",
+        "extensions": [
+          ".squiggleU"
+        ],
+        "aliases": [
+          "SquiggleU"
+        ],
+        "configuration": "./language-configuration.json"
       }
     ],
     "grammars": [
@@ -40,6 +50,11 @@
         "language": "squiggle",
         "scopeName": "source.squiggle",
         "path": "./syntaxes/squiggle.tmLanguage.json"
+      },
+      {
+        "language": "squiggleU",
+        "scopeName": "source.squiggle",
+        "path": "./syntaxes/squiggle.tmLanguage.json"
       }
     ],
     "customEditors": [