diff -r 000000000000 -r 6474c204b198 build/docs/mozbuild/dumbmake.rst
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/build/docs/mozbuild/dumbmake.rst	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,38 @@
+dumbmake
+========
+
+*dumbmake* is a simple dependency tracker for make.
+
+It turns lists of make targets into longer lists of make targets that
+include dependencies.  For example:
+
+    netwerk, package
+
+might be turned into
+
+    netwerk, netwerk/build, toolkit/library, package
+
+The dependency list is read from the plain text file
+`topsrcdir/build/dumbmake-dependencies`.  The format best described by
+example:
+
+    build_this
+        when_this_changes
+
+Interpret this to mean that `build_this` is a dependency of
+`when_this_changes`.  More formally, a line (CHILD) indented more than
+the preceding line (PARENT) means that CHILD should trigger building
+PARENT.  That is, building CHILD will trigger building first CHILD and
+then PARENT.
+
+This structure is recursive:
+
+    build_this_when_either_change
+        build_this_only_when
+            this_changes
+
+This means that `build_this_when_either_change` is a dependency of
+`build_this_only_when` and `this_changes`, and `build_this_only_when`
+is a dependency of `this_changes`.  Building `this_changes` will build
+first `this_changes`, then `build_this_only_when`, and finally
+`build_this_when_either_change`.