diff --git a/xsoft/graphweb/firefox.xml b/xsoft/graphweb/firefox.xml
index b14ebc0dc1..e686faa75b 100644
--- a/xsoft/graphweb/firefox.xml
+++ b/xsoft/graphweb/firefox.xml
@@ -146,6 +146,7 @@ tar: Exiting with failure status due to previous errors
         now deprecated by mozilla), in either case please read the
         Configuration Information,
       <xref linkend="python3"/> (rebuilt after installing <xref linkend="sqlite"/>),
+      <xref linkend="six"/>,
       <xref linkend="startup-notification"/>, and
       <xref linkend="unzip"/>
     </para>
diff --git a/xsoft/other/thunderbird.xml b/xsoft/other/thunderbird.xml
index bb73e444da..94e6571276 100644
--- a/xsoft/other/thunderbird.xml
+++ b/xsoft/other/thunderbird.xml
@@ -85,6 +85,7 @@
       <xref linkend="pulseaudio"/> (or <xref linkend="alsa-lib"/> if you edit
       the mozconfig; although it is now deprecated by mozilla),
       <xref linkend="python3"/> (rebuilt with the sqlite module),
+      <xref linkend="six"/>,
       <xref linkend="startup-notification"/>, and
       <xref linkend="unzip"/>
       <!--<xref linkend="yasm"/>-->