diff --git a/daemon/libvirtd.conf b/daemon/libvirtd.conf
index 514e6e4813bd894bf793b838e7d16e3949e239de..5485f98539fffe6bae0efc4c68f84943818340b1 100644
--- a/daemon/libvirtd.conf
+++ b/daemon/libvirtd.conf
@@ -344,10 +344,16 @@
 # The format for a filter is one of:
 #    x:name
 #    x:+name
-#      where name is a string which is matched against source file name,
-#      e.g., "remote", "qemu", or "util/json", the optional "+" prefix
-#      tells libvirt to log stack trace for each message matching name,
-#      and x is the minimal level where matching messages should be logged:
+
+#      where name is a string which is matched against the category
+#      given in the VIR_LOG_INIT() at the top of each libvirt source
+#      file, e.g., "remote", "qemu", or "util.json" (the name in the
+#      filter can be a substring of the full category name, in order
+#      to match multiple similar categories), the optional "+" prefix
+#      tells libvirt to log stack trace for each message matching
+#      name, and x is the minimal level where matching messages should
+#      be logged:
+
 #    1: DEBUG
 #    2: INFO
 #    3: WARNING
diff --git a/docs/logging.html.in b/docs/logging.html.in
index d8d8f1e89933eb9c6218f86932adccd0a871b210..b6dc91cd581603a045cd27c9622bf2fa65d8100c 100644
--- a/docs/logging.html.in
+++ b/docs/logging.html.in
@@ -104,12 +104,15 @@
     <pre>
   x:name  (log message only)
   x:+name (log message + stack trace)</pre>
-    <p>where <code>name</code> is a string which is matched against source
-    file name, e.g., <code>remote</code>, <code>qemu</code>, or
-    <code>util/json</code>, the optional <code>+</code> prefix tells libvirt
-    to log stack trace for each message matching <code>name</code>, and
-    <code>x</code> is the minimal level where matching messages should
-    be logged:</p>
+    <p>where <code>name</code> is a string which is matched against
+    the category given in the VIR_LOG_INIT() at the top of each
+    libvirt source file, e.g., <code>remote</code>, <code>qemu</code>,
+    or <code>util.json</code> (the name in the filter can be a
+    substring of the full category name, in order to match multiple
+    similar categories), the optional <code>+</code> prefix tells
+    libvirt to log stack trace for each message
+    matching <code>name</code>, and <code>x</code> is the minimal
+    level where matching messages should be logged:</p>
     <ul>
       <li>1: DEBUG</li>
       <li>2: INFO</li>