--- a/.gitignore
+++ b/.gitignore
@@ -117,8 +117,12 @@ testing/talos/talos/tests/tp5n.zip
 testing/talos/talos/tests/tp5n
 testing/talos/talos/tests/devtools/damp.manifest.develop
 
 # Ignore files created when running a reftest.
 lextab.py
 
 # tup database
 /.tup
+
+# Ignore Visual Studio Code workspace files.
+.vscode/
+!.vscode/extensions.json

--- a/.hgignore
+++ b/.hgignore
@@ -132,10 +132,12 @@ GPATH
 ^talos-venv
 
 # Ignore files created when running a reftest.
 ^lextab.py$
 
 # tup database
 ^\.tup
 
+# Ignore Visual Studio Code workspace files.
+\.vscode/(?!extensions.json$)
+
 subinclude:servo/.hgignore
-

new file mode 100644
--- /dev/null
+++ b/.vscode/extensions.json
@@ -0,0 +1,18 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        // Trim only touched lines.
+        "NathanRidley.autotrim",
+        // JS Babel ES6/ES7 syntax hilight.
+        "dzannotti.vscode-babel-coloring",
+        // ESLint support.
+        "dbaeumer.vscode-eslint",
+        // C/C++ language support.
+        "ms-vscode.cpptools",
+        // Rust language support.
+        "kalitaalexey.vscode-rust",
+        // CSS support for HTML documents.
+        "ecmel.vscode-html-css"
+    ]
+}