diff --git a/qutebrowser/utils/log.py b/qutebrowser/utils/log.py
index 403222382..3868f5fd7 100644
--- a/qutebrowser/utils/log.py
+++ b/qutebrowser/utils/log.py
@@ -256,32 +256,35 @@ def qt_message_handler(msg_type, context, msg):
     except AttributeError:
         # Qt < 5.5
         pass
+
     # Change levels of some well-known messages to debug so they don't get
     # shown to the user.
-    # suppressed_msgs is a list of regexes matching the message texts to hide.
+    #
+    # If a message starts with any text in suppressed_msgs, it's not logged as
+    # error.
     suppressed_msgs = [
         # PNGs in Qt with broken color profile
         # https://bugreports.qt.io/browse/QTBUG-39788
-        "libpng warning: iCCP: Not recognizing known sRGB profile that has "
-        "been edited",
+        'libpng warning: iCCP: Not recognizing known sRGB profile that has '
+            'been edited',
         # Hopefully harmless warning
-        "OpenType support missing for script ",
+        'OpenType support missing for script ',
         # Error if a QNetworkReply gets two different errors set. Harmless Qt
         # bug on some pages.
         # https://bugreports.qt.io/browse/QTBUG-30298
-        "QNetworkReplyImplPrivate::error: Internal problem, this method must "
-        "only be called once.",
+        'QNetworkReplyImplPrivate::error: Internal problem, this method must '
+            'only be called once.',
         # Sometimes indicates missing text, but most of the time harmless
-        "load glyph failed ",
+        'load glyph failed ',
         # Harmless, see https://bugreports.qt.io/browse/QTBUG-42479
-        "content-type missing in HTTP POST, defaulting to "
-        "application/x-www-form-urlencoded. Use QNetworkRequest::setHeader() "
-        "to fix this problem.",
+        'content-type missing in HTTP POST, defaulting to '
+            'application/x-www-form-urlencoded. '
+            'Use QNetworkRequest::setHeader() to fix this problem.',
         # https://bugreports.qt.io/browse/QTBUG-43118
-        "Using blocking call!",
+        'Using blocking call!',
         # Hopefully harmless
         '"Method "GetAll" with signature "s" on interface '
-        '"org.freedesktop.DBus.Properties" doesn\'t exist',
+            '"org.freedesktop.DBus.Properties" doesn\'t exist',
         'WOFF support requires QtWebKit to be built with zlib support.',
         # Weird Enlightment/GTK X extensions
         'QXcbWindow: Unhandled client message: "_E_',
@@ -292,9 +295,10 @@ def qt_message_handler(msg_type, context, msg):
     ]
     if sys.platform == 'darwin':
         suppressed_msgs += [
-            "libpng warning: iCCP: known incorrect sRGB profile",
-            "virtual void QSslSocketBackendPrivate::transmit() SSLRead failed "
-                "with: -9805",
+            'libpng warning: iCCP: known incorrect sRGB profile',
+            # https://bugreports.qt.io/browse/QTBUG-47154
+            'virtual void QSslSocketBackendPrivate::transmit() SSLRead failed '
+                'with: -9805',
         ]
 
     if any(msg.strip().startswith(pattern) for pattern in suppressed_msgs):