---
  Add the lv5:rctrl_switch option to xkeyboard-config for Debian 11.
  This isn't in a release until xkeyboard-config v2.36, which doesn't
  look like it will make it to Debian 12 either.

  Apply it (as root) with:

    cd /usr/share/X11/xkb/rules
    patch -p1 < /path/to/this/file.patch

diff -u a/base b/base
--- a/base	2023-01-21 18:50:42.595802084 +0000
+++ b/base	2023-01-21 18:52:11.013674023 +0000
@@ -1249,6 +1249,7 @@
   lv3:lsgt_switch_latch              =       +level3(lsgt_switch_latch)
   lv5:lsgt_switch                 =       +level5(lsgt_switch)
   lv5:ralt_switch                 =       +level5(ralt_switch)
+  lv5:rctrl_switch                =       +level5(rctrl_switch)
   lv5:lsgt_switch_lock            =       +level5(lsgt_switch_lock)
   lv5:ralt_switch_lock            =       +level5(ralt_switch_lock)
   lv5:lwin_switch_lock            =       +level5(lwin_switch_lock)
diff -u a/base.xml b/base.xml
--- a/base.xml	2023-01-21 18:50:42.599801988 +0000
+++ b/base.xml	2023-01-21 18:55:21.273064361 +0000
@@ -7342,6 +7342,12 @@
       </option>
       <option>
         <configItem>
+          <name>lv5:rctrl_switch</name>
+          <description>Right Ctrl chooses 5th level</description>
+        </configItem>
+      </option>
+      <option>
+        <configItem>
           <name>lv5:lsgt_switch_lock</name>
           <description>&lt;Less/Greater&gt; chooses 5th level; acts as onetime lock when pressed together with another 5th level chooser</description>
         </configItem>
diff -u a/evdev b/evdev
--- a/evdev	2023-01-21 18:50:42.595802084 +0000
+++ b/evdev	2023-01-21 18:52:55.344603327 +0000
@@ -1135,6 +1135,7 @@
   lv3:lsgt_switch_latch              =       +level3(lsgt_switch_latch)
   lv5:lsgt_switch                 =       +level5(lsgt_switch)
   lv5:ralt_switch                 =       +level5(ralt_switch)
+  lv5:rctrl_switch                =       +level5(rctrl_switch)
   lv5:lsgt_switch_lock            =       +level5(lsgt_switch_lock)
   lv5:ralt_switch_lock            =       +level5(ralt_switch_lock)
   lv5:lwin_switch_lock            =       +level5(lwin_switch_lock)