Update documentation per review

doc/source/image_description/elements.rst

@@ -1252,11 +1252,21 @@ more containers on a registry `source` server. {kiwi} will take
 this information and fetch the containers as OCI archives to
 the image. On first boot those container archives will be loaded
 into the local container backend store for the selected
-backend and the archive files gets deleted.
+backend and the archive files get deleted.
 
-Supported `backend` values as of today are `docker` and `podman`.
+Supported `backend` values are `docker` and `podman`.
 The `backend` attribute is mandatory and specifies for which
 container backend the image should be available in the system.
+The `containers` element has the following optional attributes:
+
+arch="arch"
+  The containers section can be configured to apply only for a certain
+  architecture. In this case specify the `arch` attribute with a
+  value as it is reported by :command:`uname -m`.
+
+profiles="name[,name]"
+  A list of profiles to which this containers selection applies
+  (see :ref:`image-profiles`).
 
 <containers><container>
 -----------------------
@@ -1288,6 +1298,11 @@ tag="tagname"
   Specifies the container tag to fetch. If not set the tag name
   defaults to `latest`
 
+arch="arch"
+  The container section can be configured to apply only for a certain
+  architecture. In this case specify the `arch` attribute with a
+  value as it is reported by :command:`uname -m`.
+
 .. _sec.repository:
 
 <repository>

kiwi/system/setup.py

@@ -91,7 +91,7 @@ def __init__(self, xml_state: XMLState, root_dir: str):
     def setup_registry_import(self) -> None:
         """
         Fetch container(s) and activate systemd unit to load
-        fetched containers during boot
+        containers from local oci-archive file during boot
         """
         container_files_to_load = []
         container_execs_to_load = []