More explicit description of DEPTH_PRIORITY

docs/faq.rst

@@ -45,7 +45,7 @@ Did Scrapy "steal" X from Django?
 
 Probably, but we don't like that word. We think Django_ is a great open source
 project and an example to follow, so we've used it as an inspiration for
-Scrapy. 
+Scrapy.
 
 We believe that, if something is already done well, there's no need to reinvent
 it. This concept, besides being one of the foundations for open source and free
@@ -85,6 +85,8 @@ How can I simulate a user login in my spider?
 
 See :ref:`topics-request-response-ref-request-userlogin`.
 
+.. _faq-bfo-dfo:
+
 Does Scrapy crawl in breadth-first or depth-first order?
 --------------------------------------------------------
 

docs/topics/settings.rst

@@ -292,10 +292,14 @@ Scope: ``scrapy.spidermiddlewares.depth.DepthMiddleware``
 
 An integer that is used to adjust the request priority based on its depth:
 
-- **a positive value will decrease the priority**
-- a negative value will increase priority
-
-If zero (default), no priority adjustment is made from depth.
+- if zero (default), no priority adjustment is made from depth
+- **a positive value will decrease the priority, i.e. higher depth
+  requests will be processed later** ; this is commonly used when doing
+  breadth-first crawls (BFO)
+- a negative value will increase priority, i.e., higher depth requests
+  will be processed sooner (DFO)
+
+See also: :ref:`faq-bfo-dfo` about tuning Scrapy for BFO or DFO.
 
 .. note::