Looks like it was removed from bionic due to bug 1748000. (Found via the publishing history link in the upper right corner on the package overview page, see https://launchpad.net/ubuntu/+source/nvidia-graphics- drivers-304/+publishinghistory for details)
** Package changed: ubuntu => nvidia-graphics-drivers-304 (Ubuntu) -- You received this bug notification because you are a member of Ubuntu-X, which is subscribed to nvidia-graphics-drivers-304 in Ubuntu. https://bugs.launchpad.net/bugs/1763648 Title: nvidia-304 (304.137) missing in Ubuntu 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-304/+bug/1763648/+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