Restricted environment matrix test but it's weird syntax

Author: PathogenDavid

.github/workflows/matrix-environment.yml

@@ -0,0 +1,18 @@
+name: Restricted Environment Test (Matrix)
+on: [workflow_dispatch]
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-latest
+            environment:
+          - os: ubuntu-18.04
+            environment: "environment: TestEnvironment"
+    name: Test Job - ${{matrix.os}} (${{matrix.environment}})
+    runs-on: ubuntu-latest
+    ${{matrix.environment}}
+    steps:
+      - name: Do the thing
+        run: echo "Hello, world!"