feat: Add new gcloud commands, API clients, and third-party libraries across various services.

gcloud auth application-default login/google-cloud-sdk/lib/surface/privateca/roots/describe.yaml

@@ -0,0 +1,32 @@
+- release_tracks: [GA]
+  help_text:
+    brief: |
+      Get metadata for a root Certificate Authority.
+    description: |
+      Returns metadata for the given Certificate Authority.
+    examples: |
+      To get metadata for the root CA 'prod-root' in location 'us-west1' and CA Pool 'my-pool':
+
+        $ {command} server-tls-1 \
+            --location=us-west1 --pool=my-pool
+
+      To download the PEM-encoded CA certificate chain for the 'prod-root'
+      CA in location 'us-west1' and CA Pool 'my-pool' to a file
+      called 'prod-root.crt':
+
+        $ {command} prod-root \
+            --location=us-west1 --pool=my-pool \
+            --format="value(pemCaCertificates)" > ./prod-root.crt
+
+  request:
+    collection: privateca.projects.locations.caPools.certificateAuthorities
+    api_version: v1
+
+  arguments:
+    resource:
+      help_text: The certificate authority for which to obtain metadata.
+      spec: !REF googlecloudsdk.command_lib.privateca.resources:cert_authority
+
+  response:
+    modify_response_hooks:
+    - googlecloudsdk.command_lib.privateca.hooks:CheckResponseRootTypeHook:version=v1