man: add note that %h/%u/%U are mostly useless

Fixes #12389.

diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index 3079db1a6ba6177e12e031e2c05b3b5f2611fd1c..d13212ebcc51bda59bffb885a4055113aaf773a9 100644 (file)
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -1607,7 +1607,9 @@
           <row>
             <entry><literal>%h</literal></entry>
             <entry>User home directory</entry>
-            <entry>This is the home directory of the user running the service manager instance. In case of the system manager this resolves to <literal>/root</literal>.</entry>
+            <entry>This is the home directory of the <emphasis>user running the service manager instance</emphasis>. In case of the system manager this resolves to <literal>/root</literal>.
+
+Note that this setting is <emphasis>not</emphasis> influenced by the <varname>User=</varname> setting configurable in the [Service] section of the service unit.</entry>
           </row>
           <row>
             <entry><literal>%H</literal></entry>
@@ -1697,12 +1699,16 @@
           <row>
             <entry><literal>%u</literal></entry>
             <entry>User name</entry>
-            <entry>This is the name of the user running the service manager instance. In case of the system manager this resolves to <literal>root</literal>.</entry>
+            <entry>This is the name of the <emphasis>user running the service manager instance</emphasis>. In case of the system manager this resolves to <literal>root</literal>.
+
+Note that this setting is <emphasis>not</emphasis> influenced by the <varname>User=</varname> setting configurable in the [Service] section of the service unit.</entry>
           </row>
           <row>
             <entry><literal>%U</literal></entry>
             <entry>User UID</entry>
-            <entry>This is the numeric UID of the user running the service manager instance. In case of the system manager this resolves to <literal>0</literal>.</entry>
+            <entry>This is the numeric UID of the <emphasis>user running the service manager instance</emphasis>. In case of the system manager this resolves to <literal>0</literal>.
+
+Note that this setting is <emphasis>not</emphasis> influenced by the <varname>User=</varname> setting configurable in the [Service] section of the service unit.</entry>
           </row>
           <row>
             <entry><literal>%v</literal></entry>