diff --git a/containers/azure-functions-dotnetcore-2.1/.devcontainer/Dockerfile b/containers/azure-functions-dotnetcore-2.1/.devcontainer/Dockerfile
index 9e96b1026f..cb9606d280 100644
--- a/containers/azure-functions-dotnetcore-2.1/.devcontainer/Dockerfile
+++ b/containers/azure-functions-dotnetcore-2.1/.devcontainer/Dockerfile
@@ -12,7 +12,7 @@ RUN apt-get update && apt-get -y install git procps
 RUN apt-get install -y apt-transport-https curl gnupg2 lsb-release \
     && echo "deb [arch=amd64] https://packages.microsoft.com/repos/azure-cli/ $(lsb_release -cs) main" > /etc/apt/sources.list.d/azure-cli.list \
     && echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-debian-$(lsb_release -cs)-prod $(lsb_release -cs) main" > /etc/apt/sources.list.d/dotnetdev.list \
-    && curl -L https://packages.microsoft.com/keys/microsoft.asc | apt-key add - \
+    && curl -L https://packages.microsoft.com/keys/microsoft.asc | apt-key add - 2>/dev/null \
     && apt-get update \
     && apt-get install -y azure-cli azure-functions-core-tools
     
diff --git a/containers/azure-functions-dotnetcore-latest/.devcontainer/Dockerfile b/containers/azure-functions-dotnetcore-latest/.devcontainer/Dockerfile
index 395efc172d..fb772c7d80 100644
--- a/containers/azure-functions-dotnetcore-latest/.devcontainer/Dockerfile
+++ b/containers/azure-functions-dotnetcore-latest/.devcontainer/Dockerfile
@@ -12,7 +12,7 @@ RUN apt-get update && apt-get -y install git procps
 RUN apt-get install -y apt-transport-https curl gnupg2 lsb-release \
     && echo "deb [arch=amd64] https://packages.microsoft.com/repos/azure-cli/ $(lsb_release -cs) main" > /etc/apt/sources.list.d/azure-cli.list \
     && echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-debian-$(lsb_release -cs)-prod $(lsb_release -cs) main" > /etc/apt/sources.list.d/dotnetdev.list \
-    && curl -L https://packages.microsoft.com/keys/microsoft.asc | apt-key add - \
+    && curl -L https://packages.microsoft.com/keys/microsoft.asc | apt-key add - 2>/dev/null \
     && apt-get update \
     && apt-get install -y azure-cli azure-functions-core-tools
 
diff --git a/containers/azure-machine-learning-python-3/.devcontainer/Dockerfile b/containers/azure-machine-learning-python-3/.devcontainer/Dockerfile
index f890941103..e34f157064 100644
--- a/containers/azure-machine-learning-python-3/.devcontainer/Dockerfile
+++ b/containers/azure-machine-learning-python-3/.devcontainer/Dockerfile
@@ -10,7 +10,7 @@ RUN apt-get update && apt-get -y install git procps
 
 # Install Docker CE - ** COMMENT OUT IF YOU WILL ONLY RUN LOCAL OR IN AZURE **
 RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common \
-    && curl -fsSL https://download.docker.com/linux/debian/gpg | apt-key add - \
+    && curl -fsSL https://download.docker.com/linux/debian/gpg | apt-key add - 2>/dev/null \
     && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/debian $(lsb_release -cs) stable" \
     && apt-get update \
     && apt-get install -y docker-ce-cli
diff --git a/containers/docker-in-docker-compose/.devcontainer/Dockerfile b/containers/docker-in-docker-compose/.devcontainer/Dockerfile
index d024c629ca..11c332c389 100644
--- a/containers/docker-in-docker-compose/.devcontainer/Dockerfile
+++ b/containers/docker-in-docker-compose/.devcontainer/Dockerfile
@@ -11,7 +11,7 @@ RUN apt-get update && apt-get -y install git procps
 
 # Install Docker CE CLI
 RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
     && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
     && apt-get update \
     && apt-get install -y docker-ce-cli
diff --git a/containers/docker-in-docker-compose/README.md b/containers/docker-in-docker-compose/README.md
index e1ab0d4b7e..2f39bc6169 100644
--- a/containers/docker-in-docker-compose/README.md
+++ b/containers/docker-in-docker-compose/README.md
@@ -24,7 +24,7 @@ You can adapt your own existing development container Docker Compose setup to su
 
     ```Dockerfile
     RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
         && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
         && apt-get update \
         && apt-get install -y docker-ce-cli
diff --git a/containers/docker-in-docker/.devcontainer/Dockerfile b/containers/docker-in-docker/.devcontainer/Dockerfile
index e113c53607..dd30feeb66 100644
--- a/containers/docker-in-docker/.devcontainer/Dockerfile
+++ b/containers/docker-in-docker/.devcontainer/Dockerfile
@@ -12,7 +12,7 @@ RUN apt-get update && apt-get -y install git procps
 
 # Install Docker CE CLI
 RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
     && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
     && apt-get update \
     && apt-get install -y docker-ce-cli
diff --git a/containers/docker-in-docker/README.md b/containers/docker-in-docker/README.md
index 1a7c3948b3..438ec59cd4 100644
--- a/containers/docker-in-docker/README.md
+++ b/containers/docker-in-docker/README.md
@@ -25,7 +25,7 @@ You can adapt your own existing development container Dockerfile to support this
     ```Dockerfile
     # Install Docker CE CLI
     RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
         && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
         && apt-get update \
         && apt-get install -y docker-ce-cli
diff --git a/containers/kubernetes-helm/.devcontainer/Dockerfile b/containers/kubernetes-helm/.devcontainer/Dockerfile
index 71c19ddb1e..57f4d559df 100644
--- a/containers/kubernetes-helm/.devcontainer/Dockerfile
+++ b/containers/kubernetes-helm/.devcontainer/Dockerfile
@@ -11,13 +11,13 @@ RUN apt-get update && apt-get -y install git procps
 
 # Install Docker CE CLI
 RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+    && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
     && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
     && apt-get update \
     && apt-get install -y docker-ce-cli
 
 # Install kubectl
-RUN curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - \
+RUN curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - 2>/dev/null \
     && echo "deb https://apt.kubernetes.io/ kubernetes-$(lsb_release -cs) main" | tee -a /etc/apt/sources.list.d/kubernetes.list \
     && apt-get update \
     && apt-get install -y kubectl
diff --git a/containers/kubernetes-helm/README.md b/containers/kubernetes-helm/README.md
index 743988969f..e6f61e4163 100644
--- a/containers/kubernetes-helm/README.md
+++ b/containers/kubernetes-helm/README.md
@@ -27,13 +27,13 @@ You can adapt your own existing development container Dockerfile to support this
     ```Dockerfile
     # Install Docker CE CLI
     RUN apt-get install -y apt-transport-https ca-certificates curl gnupg-agent software-properties-common lsb-release \
-        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - \
+        && curl -fsSL https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]')/gpg | apt-key add - 2>/dev/null \
         && add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/$(lsb_release -is | tr '[:upper:]' '[:lower:]') $(lsb_release -cs) stable" \
         && apt-get update \
         && apt-get install -y docker-ce-cli
 
     # Install kubectl
-    RUN curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - \
+    RUN curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - 2>/dev/null \
         && echo "deb https://apt.kubernetes.io/ kubernetes-$(lsb_release -cs) main" | tee -a /etc/apt/sources.list.d/kubernetes.list \
         && apt-get update \
         && apt-get install -y kubectl
diff --git a/containers/markdown/vscode-docs b/containers/markdown/vscode-docs
new file mode 160000
index 0000000000..6e6357ef08
--- /dev/null
+++ b/containers/markdown/vscode-docs
@@ -0,0 +1 @@
+Subproject commit 6e6357ef08552370ffb284f7717af0e4223ab0d5
diff --git a/repository-containers/github.com/angular/angular/.devcontainer/Dockerfile b/repository-containers/github.com/angular/angular/.devcontainer/Dockerfile
index 2c017a1df8..b6dd4b8cb9 100644
--- a/repository-containers/github.com/angular/angular/.devcontainer/Dockerfile
+++ b/repository-containers/github.com/angular/angular/.devcontainer/Dockerfile
@@ -19,7 +19,7 @@ RUN curl -sL https://deb.nodesource.com/setup_10.x | bash - \
     && apt-get install -y nodejs
 
 # Install yarn
-RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - \
+RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - 2>/dev/null \
     && echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list \
     && apt-get update && apt-get install yarn=1.13.0-1