diff --git a/documentation/dev-manual/common-tasks.rst b/documentation/dev-manual/common-tasks.rst
index b08a55331d..3112f9b893 100644
--- a/documentation/dev-manual/common-tasks.rst
+++ b/documentation/dev-manual/common-tasks.rst
@@ -2577,7 +2577,7 @@ chapter of the BitBake User Manual.
 
       S = "${WORKDIR}/postfix-${PV}"
       CFLAGS += "-DNO_ASM"
-      SRC_URI:append = " file://fixup.patch"
+      CFLAGS:append = " --enable-important-feature"
 
 -  *Functions:* Functions provide a series of actions to be performed.
    You usually use functions to override the default implementation of a
@@ -2708,19 +2708,20 @@ in the BitBake User Manual.
    to existing variables. This operator does not add any additional
    space. Also, the operator is applied after all the ``+=``, and ``=+``
    operators have been applied and after all ``=`` assignments have
-   occurred.
+   occurred. This means that if ``:append`` is used, that text can not be
+   removed.
 
    The following example shows the space being explicitly added to the
    start to ensure the appended value is not merged with the existing
    value::
 
-      SRC_URI:append = " file://fix-makefile.patch"
+      CFLAGS:append = " --enable-important-feature"
 
    You can also use
    the ``:append`` operator with overrides, which results in the actions
    only being performed for the specified target or machine::
 
-      SRC_URI:append:sh4 = " file://fix-makefile.patch"
+      CFLAGS:append:sh4 = " --enable-important-sh4-specific-feature"
 
 -  *Prepending (:prepend):* Use the ``:prepend`` operator to prepend
    values to existing variables. This operator does not add any