diff --git a/Dockerfile b/Dockerfile
index 45d3d90..4b81875 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,6 +10,7 @@ WORKDIR /app
 
 COPY script/ script/
 COPY package.json yarn.lock ./
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 RUN script/bootstrap
 
 COPY . .
diff --git a/script/bootstrap b/script/bootstrap
index a0a19ef..948a34e 100755
--- a/script/bootstrap
+++ b/script/bootstrap
@@ -118,6 +118,7 @@ ensure_yarn() {
     fi
 }
 
+# yarn warns about the workspaces field in eslint and babel-plugin-istanbul; no newer release drops it.
 install_js_deps() {
     if missing yarn && [ -s "$HOME/.nvm/nvm.sh" ]; then
         nvm_sh "nvm use $NODE_VERSION >/dev/null && cd \"$ROOT\" && \