diff --git a/documentation/content/en/books/porters-handbook/makefiles/_index.adoc b/documentation/content/en/books/porters-handbook/makefiles/_index.adoc
--- a/documentation/content/en/books/porters-handbook/makefiles/_index.adoc
+++ b/documentation/content/en/books/porters-handbook/makefiles/_index.adoc
@@ -4100,6 +4100,34 @@
 Build targets::
 When an option need some extra processing, see <<options-targets>>.
 
+[[flavors_sub]]
+==== `FLAVORS_SUB\
+
+If `FLAVORS_SUB` is set to `yes` then each of the flavors added to `FLAVORS` will be added to `PLIST_SUB` and `SUB_LIST`, for example:
+
+[.programlisting]
+....
+FLAVORS=	flav1 flav2
+FLAVORS_SUB=	yes
+....
+
+is equivalent to:
+[.programlisting]
+....
+FLAVORS=	flav1 flav2
+
+.include <bsd.port.pre.mk>
+.if ${FLAVOR} == flav1
+PLIST_SUB=	FLAV1="" NO_FLAV1="@comment " FLAV2="@comment " NO_FLAV2=""
+SUB_LIST=	FLAV1="" NO_FLAV1="@comment " FLAV2="@comment " NO_FLAV2=""
+.fi
+.if ${FLAVOR} == flav2
+PLIST_SUB=	FLAV2="" NO_FLAV2="@comment " FLAV1="@comment " NO_FLAV1=""
+SUB_LIST=	FLAV2="" NO_FLAV2="@comment " FLAV1="@comment " NO_FLAV1=""
+.fi
+.include <bsd.port.post.mk>
+....
+
 [[options_sub]]
 ==== `OPTIONS_SUB`
 
diff --git a/documentation/content/en/books/porters-handbook/plist/_index.adoc b/documentation/content/en/books/porters-handbook/plist/_index.adoc
--- a/documentation/content/en/books/porters-handbook/plist/_index.adoc
+++ b/documentation/content/en/books/porters-handbook/plist/_index.adoc
@@ -54,6 +54,24 @@
 in the [.filename]#Makefile# and use `%%OCTAVE_VERSION%%` wherever the version shows up in [.filename]#pkg-plist#.
 When the port is upgraded, it will not be necessary to edit dozens (or in some cases, hundreds) of lines in [.filename]#pkg-plist#.
 
+If files are installed conditionally on the flavors set in the port, the usual way of handling it is prefixing [.filename]#pkg-plist# lines with a `%%FLAV%%` for lines needed when the flavor is enabled, or `%%NO_FLAV%%` when the flavor is disabled, and adding `FLAVORS_SUB=yes` to the [.filename]#Makefile#.
+See crossref:makefiles[flavors_sub,`FLAVORS_SUB`] for more information.
+
+For instance, if there arefiles that are only installed when the `X11` flavor is enabled, and [.filename]#Makefile has:
+
+[.programlisting]
+....
+FLAVORS=	X11 console
+FLAVORS_SUB=	yes
+....
+
+In [.filename]#pkg-plist#, `%%X11%%` in front of the lines only being installed when the flavor is enabled, like this:
+
+[.programlisting]
+....
+%%X11%%bin/foo-gui
+....
+
 If files are installed conditionally on the options set in the port, the usual way of handling it is prefixing [.filename]#pkg-plist# lines with a `%%OPT%%` for lines needed when the option is enabled, or `%%NO_OPT%%` when the option is disabled, and adding `OPTIONS_SUB=yes` to the [.filename]#Makefile#.
 See crossref:makefiles[options_sub,`OPTIONS_SUB`] for more information.