+### Atom responses
+
+These responses **should** be served with a `Content-Type` of
+ `application/atom+xml`.
+In all cases, for `/$PATH.atom`, this just serves the file at
+ `/$PATH/index.atom`.
+
+ + **`GET /statuses.atom`**:
+ Serve the file at `/statuses/index.atom`.
+
+ + **`GET /statuses/$YYYY-MM.atom`** (where `$YYYY-MM` is an
+ `xsd:gYearMonth`):
+ Serve the file at `/$YYYY-MM/index.atom`.
+
+ + **`GET /topics/$TOPIC.atom`** (where `$TOPIC` matches
+ `[0-9A-Za-z_-]+`):
+ Serve the file at `/topics/$TOPIC/index.atom`.
+