diff --git a/scrapy/http/response/html.py b/scrapy/http/response/html.py
index 70c08c11d..6d3a9ee12 100644
--- a/scrapy/http/response/html.py
+++ b/scrapy/http/response/html.py
@@ -1,6 +1,7 @@
 """
-This module implements the HtmlResponse class which adds encoding
-discovering through HTML encoding declarations to the TextResponse class.
+This module implements the :class:`HtmlResponse` class which is used as a
+content type marker by :class:`~scrapy.selector.Selector` and can be used in
+``isinstance()`` checks.
 
 See documentation in docs/topics/request-response.rst
 """
diff --git a/scrapy/http/response/xml.py b/scrapy/http/response/xml.py
index 6d9c4cb73..847fb2b3c 100644
--- a/scrapy/http/response/xml.py
+++ b/scrapy/http/response/xml.py
@@ -1,6 +1,7 @@
 """
-This module implements the XmlResponse class which adds encoding
-discovering through XML encoding declarations to the TextResponse class.
+This module implements the :class:`XmlResponse` class which is used as a
+content type marker by :class:`~scrapy.selector.Selector` and can be used in
+``isinstance()`` checks.
 
 See documentation in docs/topics/request-response.rst
 """