They're not coming from the server, but directly from the apps running on the user session. Since the login manager is starting the user session, it could be possible to route stderr to some external app for adding the timestamps..
** Changed in: xorg-server (Ubuntu) Status: New => Invalid ** Package changed: xorg-server (Ubuntu) => lightdm (Ubuntu) ** Changed in: lightdm (Ubuntu) Status: Invalid => New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1088343 Title: please timestamp entries in .xsession-errors To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1088343/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs