diff --git a/wiki/cue_sheet.md b/wiki/cue_sheet.md
new file mode 100644
index 0000000..0ba66cc
--- /dev/null
+++ b/wiki/cue_sheet.md
@@ -0,0 +1,51 @@
+# Cue sheet
+
+A cue sheet is a metadata file containing information for the tracks of a CD or
+a file [ripped](./audio.md#extract-audio-files-from-cds) from it.
+
+## Example file
+
+To understand the structure of a cue file the following lines show the contents
+of an example cue file. All lines starting with `REM`, `PERFORMER` or `TITLE`
+are optional. The following example is taken from the
+[wikipedia article](https://en.wikipedia.org/wiki/Cue_sheet_(computing)):
+
+```cue
+REM GENRE Electronica
+REM DATE 1998
+PERFORMER "Faithless"
+TITLE "Live in Berlin"
+FILE "Faithless - Live in Berlin.mp3" MP3
+  TRACK 01 AUDIO
+    TITLE "Reverence"
+    PERFORMER "Faithless"
+    INDEX 01 00:00:00
+  TRACK 02 AUDIO
+    TITLE "She's My Baby"
+    PERFORMER "Faithless"
+    INDEX 01 06:42:00
+  TRACK 03 AUDIO
+    TITLE "Take the Long Way Home"
+    PERFORMER "Faithless"
+    INDEX 01 10:54:00
+  TRACK 04 AUDIO
+    TITLE "Insomnia"
+    PERFORMER "Faithless"
+    INDEX 01 17:04:00
+  TRACK 05 AUDIO
+    TITLE "Bring the Family Back"
+    PERFORMER "Faithless"
+    INDEX 01 25:44:00
+  TRACK 06 AUDIO
+    TITLE "Salva Mea"
+    PERFORMER "Faithless"
+    INDEX 01 30:50:00
+  TRACK 07 AUDIO
+    TITLE "Dirty Old Man"
+    PERFORMER "Faithless"
+    INDEX 01 38:24:00
+  TRACK 08 AUDIO
+    TITLE "God Is a DJ"
+    PERFORMER "Faithless"
+    INDEX 01 42:35:00
+```
diff --git a/wiki/linux/flac_(package).md b/wiki/linux/flac_(package).md
index 02b9fba..3d68b13 100644
--- a/wiki/linux/flac_(package).md
+++ b/wiki/linux/flac_(package).md
@@ -10,8 +10,8 @@ Another possible tagging software is [MusicBrainz Picard](../picard.md)
 
 ## Splitting Flac file according to cue file
 
-An easy way to split flac files according to a cue file is using
-`cuebreakpoints` and `shnsplit`.
+An easy way to split flac files according to a [cue file](../cue_sheet.md) is
+using `cuebreakpoints` and `shnsplit`.
 On most distributions they are in a package with the same name.
 The following line of shell command splits a flac file according to a cue file.
 The `-o` tag specifies the output file format.
diff --git a/wiki/matrix.md b/wiki/matrix.md
index 1fa5a38..43e1f02 100644
--- a/wiki/matrix.md
+++ b/wiki/matrix.md
@@ -103,6 +103,8 @@ federation_ip_range_blacklist:
   - '::1/128'
   - 'fe80::/64'
   - 'fc00::/7'
+retention:
+  enabled: true
 ```
 
 If you start the docker container with `docker-compose up` and navigate to
@@ -301,9 +303,12 @@ section:
       - "traefik.http.routers.element-secure.rule=Host(`chat.example.com`)"
       - "traefik.http.routers.element-secure.service=element"
       - "traefik.http.services.element.loadbalancer.server.port=80"
-
 ```
 
+Add the following line to the `homeserver.yaml` of the synapse server to
+indicate your element domain:
+`web_client_location: https://chat.example.com`.
+
 Start the container.
 You should now be able to navigate to `https://chat.example.com` where you are
 prompted with a log in window.