diff --git a/app/models/concerns/blob_virus_scanner.rb b/app/models/concerns/blob_virus_scanner.rb
index 4cd5f8476..c6b0966c9 100644
--- a/app/models/concerns/blob_virus_scanner.rb
+++ b/app/models/concerns/blob_virus_scanner.rb
@@ -1,3 +1,7 @@
+# TODO: once we're using Rails 6, use the hooks on attachments creation
+# (rather than on blob creation).
+# This will help to avoid cloberring metadata accidentally (as metadata
+# are more stable on attachment creation than on blob creation).
 module BlobVirusScanner
   extend ActiveSupport::Concern
 
diff --git a/config/initializers/active_storage.rb b/config/initializers/active_storage.rb
index e9fb875dd..7357c9267 100644
--- a/config/initializers/active_storage.rb
+++ b/config/initializers/active_storage.rb
@@ -1,3 +1,9 @@
 ActiveStorage::Service.url_expires_in = 1.hour
 
+# In Rails 5.2, we have to hook at `on_load` on the blob themeselves, which is
+# not ideal.
+#
+# Rails 6 adds support for `.on_load(:active_storage_attachment)`, which is
+# cleaner (as it allows to enqueue the virus scan on attachment creation, rather
+# than on blob creation).
 ActiveSupport.on_load(:active_storage_blob) { include BlobVirusScanner }