diff --git a/config/_default/mediatypes.yaml b/config/_default/mediatypes.yaml
index af75d0b..ae59f7f 100644
--- a/config/_default/mediatypes.yaml
+++ b/config/_default/mediatypes.yaml
@@ -3,4 +3,4 @@ application/rss+xml:
   suffixes: [rss]
 application/atom+xml:
   delimiter: .
-  suffixes: [xml]
+  suffixes: [atom, xml]
diff --git a/config/_default/outputformats.yaml b/config/_default/outputformats.yaml
index ff45b97..5ff4e1d 100644
--- a/config/_default/outputformats.yaml
+++ b/config/_default/outputformats.yaml
@@ -5,4 +5,4 @@ RSS:
 Atom:
   mediatype: application/atom+xml
   baseName: feed
-  suffixes: [xml]
+  suffixes: [atom, xml]
diff --git a/layouts/_default/index.atom.xml b/layouts/_default/index.atom.atom
similarity index 100%
rename from layouts/_default/index.atom.xml
rename to layouts/_default/index.atom.atom
diff --git a/layouts/_default/rss.rss b/layouts/_default/index.rss.xml
similarity index 100%
rename from layouts/_default/rss.rss
rename to layouts/_default/index.rss.xml