diff --git a/test/ci/before_install.sh b/test/ci/before_install.sh
index 93c5570b..2ccd96b6 100755
--- a/test/ci/before_install.sh
+++ b/test/ci/before_install.sh
@@ -3,6 +3,8 @@
 
 case "$TRAVIS_OS_NAME" in
   "linux")
+    # Not using Trusty containers because it can't install wine1.6(-i386),
+    # see: https://github.com/travis-ci/travis-ci/issues/6460
     sudo rm /etc/apt/sources.list.d/google-chrome.list
     sudo dpkg --add-architecture i386
     sudo apt-get update