--- a/doc/opt-freecalypso-tree	Sat Apr 02 21:52:29 2022 +0000
+++ b/doc/opt-freecalypso-tree	Sat Apr 02 23:48:53 2022 +0000
@@ -3,51 +3,52 @@
 file system hierarchy standard (FHS), instead it is a highly specialized
 directory tree that is meant to be private to FreeCalypso, with its structure
 defined solely by the Mother and no one else.  The following subdirectories are
-currently defined:
+populated by the base FC host tools package:
+
+bin		All Unix/Linux host binaries are installed here.
 
-aud-*: these directories appear if you install our optional
-fc-audio-config package, and contain subtrees to be uploaded by
-production line scripts into target device FFS under /aud via fc-fsio.
+include		rvinterf headers are installed here, allowing them to be used
+		by add-on packages like fc-rfcal-tools.
 
-batteries and charging: these subtrees come from fc-battery-conf
-(optional just like fc-audio-config) and are meant to be used with
-fc-fsio write-battery-table and write-charging-config commands.
+helpfiles	Help files for those FC host utilities which implement a help
+		command.
 
-bin and include are the only subdirectories under /opt/freecalypso
-which follow traditional UNIX directory layout; include was added so
-that packages external to the core FC host tools package like
-fc-rfcal-tools and freecalypso-ui-dev can use rvinterf headers.
+loadtools	Hardware parameter files and init scripts which underlie the
+		all-important -h option to fc-loadtool, fc-iram and fc-xram,
+		collectively known as loadtools.
 
-gcc: the recommend install location for our ARM7 gcc toolchain is
-/opt/freecalypso/gcc.
+scripts		Command scripts for FC host tools other than fc-loadtool,
+		currently for fc-fsio.
 
-helpfiles subdir contains help files for those FC host utilities which
-implement a help command.
+target-bin	ARM7 target binaries used under the hood by loadtools.
+
+The following additional subdirectories will be populated by the add-on FC FFS
+bundle package:
 
-loadtools subdir contains hardware parameter files and init scripts
-which underlie the all-important -h option to fc-loadtool, fc-iram and
-fc-xram, collectively known as loadtools.
+aud-*		Images of /aud FFS directory subtree (audio mode config files)
+		for different supported FreeCalypso devices, either FC hardware
+		products or aftermarket configurations.
+
+batteries	Collection of battery discharge threshold configuration files.
 
-rfcal subdir only appears if you are doing RF calibration and install
-fc-rfcal-tools, and some of the necessary config files under that
-subdir you have to create yourself using your own RF knowledge specific
-to your particular setup.
+buz		FFS subtree with PWT buzzer melodies, to be uploaded into /buz
+		on those FC devices that feature a traditional ringing buzzer -
+		see the Buzzer-melodies article.
 
-scripts subdir contains command scripts for FC host tools other than
-fc-loadtool, currently for fc-fsio.
-
-sim-data and sim-scripts subdirectories are used by the FC SIM tools package.
+charging	Collection of battery charging configuration files.
 
-target-bin contains ARM7 target binaries used under the hood by
-loadtools.
+mel		FFS subtree with E1 melodies, to be uploaded into /mel on those
+		FC devices that will use a voice path loudspeaker for ringing.
+
+Other subdirectories that are currently defined by the Mother:
+
+gcc		The recommend install location for our ARM7 gcc toolchain is
+		/opt/freecalypso/gcc.
 
-The basic minimal form of the /opt/freecalypso tree is populated when
-you install FC host tools, but it is further enriched if and when you
-install further add-ons (fc-audio-config, fc-battery-conf,
-fc-rfcal-tools) which are more specialized and not required for all
-users.  I expect to have more additions in the future: for example,
-when we start using the Melody E1 mechanism in our planned FC Libre
-Dumbphone, there will be a FreeCalypso ringtones package that will
-install E1-format melody files somewhere under /opt/freecalyso, to be
-subsequently uploaded into the actual phones via fc-fsio, initially at
-production time and optionally by end users.
+rfcal		This subdir only appears if you are doing RF calibration and
+		install fc-rfcal-tools, and some of the necessary config files
+		under that subdir you have to create yourself using your own RF
+		knowledge specific to your particular setup.
+
+sim-data	These two subdirs are used by the FC SIM tools package.
+sim-scripts