As mentioned on bug 2088433, you can create a local override if you want something different than the default. E.g. create /etc/tmpfiles.d/tmp.conf with your own configuration for /tmp.
Regarding x11.conf, this has been that way for a long time AFAICT, and I don't know enough about that package to weigh in. I realized the file is shipped by systemd, but I am adding xorg as an affected package to hopefully get someone's attention that can weigh in. ** Also affects: xorg (Ubuntu) Importance: Undecided Status: New ** Changed in: systemd (Ubuntu) Importance: Undecided => Low -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to xorg in Ubuntu. https://bugs.launchpad.net/bugs/2088268 Title: systemd /tmp cleaning removes files that it shouldn't To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/2088268/+subscriptions _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp