Just noticed this notification:
Checking logs, I find
Sep 17 22:15:50 opalvinyard systemd[1]: Starting CUPS Scheduler...
Sep 17 22:15:50 opalvinyard cupsd[80789]: No limit for Validate-Job defined in policy default and no suitable template found.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No limit for Cancel-Jobs defined in policy default - using Pause-Printer's policy.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No limit for Cancel-My-Jobs defined in policy default - using Send-Document's policy.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No limit for Close-Job defined in policy default - using Send-Document's policy.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No limit for CUPS-Get-Document defined in policy default - using Send-Document's policy.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No JobPrivateAccess defined in policy default - using defaults.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No JobPrivateValues defined in policy default - using defaults.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No SubscriptionPrivateAccess defined in policy default - using defaults.
Sep 17 22:15:50 opalvinyard cupsd[80789]: No SubscriptionPrivateValues defined in policy default - using defaults.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Remote access is disabled.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Loaded configuration file "/etc/cups/cupsd.conf"
Sep 17 22:15:50 opalvinyard cupsd[80789]: Configured for up to 100 clients.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Allowing up to 100 client connections per host.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Using policy "default" as the default.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Full reload is required.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Loaded MIME database from "/nix/store/arzrm5p643g35f0dadf8wj71i197kklb-cups-progs/share/cups/mime" and "/etc/cups": 41 types, 31 filters...
Sep 17 22:15:50 opalvinyard cupsd[80789]: Printer drivers are deprecated and will stop working in a future version of CUPS. See https://github.com/OpenPrinting/cups/issues/103
Sep 17 22:15:50 opalvinyard cupsd[80789]: Loading job cache file "/var/cache/cups/job.cache"...
Sep 17 22:15:50 opalvinyard cupsd[80789]: Full reload complete.
Sep 17 22:15:50 opalvinyard cupsd[80789]: Cleaning out old files in "/var/cache/cups".
Sep 17 22:15:50 opalvinyard cupsd[80789]: Registering ICC color profiles for "MFC-L2730DW".
Sep 17 22:15:50 opalvinyard cupsd[80789]: Listening to [v1.::1]:631 on fd 8...
Sep 17 22:15:50 opalvinyard cupsd[80789]: Listening to 127.0.0.1:631 on fd 4...
Sep 17 22:15:50 opalvinyard cupsd[80789]: Listening to /run/cups/cups.sock on fd 3...
Sep 17 22:15:50 opalvinyard cupsd[80789]: Resuming new connection processing...
Sep 17 22:15:50 opalvinyard cupsd[80789]: REQUEST localhost - - "POST / HTTP/1.1" 200 193 Renew-Subscription successful-ok
Sep 17 22:15:50 opalvinyard cupsd[80789]: REQUEST localhost - - "POST /admin/ HTTP/1.1" 401 183 CUPS-Add-Modify-Printer successful-ok
Sep 17 22:15:50 opalvinyard cupsd[80789]: Setting _tmp device-uri to "file:/dev/null" (was "file:///dev/null".)
Sep 17 22:15:50 opalvinyard cupsd[80789]: New printer "_tmp" added by "root".
Sep 17 22:15:50 opalvinyard cupsd[80789]: REQUEST localhost - root "POST /admin/ HTTP/1.1" 200 183 CUPS-Add-Modify-Printer successful-ok
Sep 17 22:15:50 opalvinyard cupsd[80789]: REQUEST localhost - - "POST /admin/ HTTP/1.1" 401 149 CUPS-Delete-Printer successful-ok
Sep 17 22:15:50 opalvinyard cupsd[80789]: Printer "_tmp" deleted by "root".
Sep 17 22:15:50 opalvinyard cupsd[80789]: REQUEST localhost - root "POST /admin/ HTTP/1.1" 200 149 CUPS-Delete-Printer successful-ok
Sep 17 22:15:50 opalvinyard cups-post-start[80794]: CUPS provisioning complete.
Sep 17 22:15:50 opalvinyard systemd[1]: Started CUPS Scheduler.
In particular, these lines:
REQUEST localhost - - "POST /admin/ HTTP/1.1" 401 183 CUPS-Add-Modify-Printer successful-ok
Setting _tmp device-uri to "file:/dev/null" (was "file:///dev/null".)
New printer "_tmp" added by "root".
REQUEST localhost - root "POST /admin/ HTTP/1.1" 200 183 CUPS-Add-Modify-Printer successful-ok
REQUEST localhost - - "POST /admin/ HTTP/1.1" 401 149 CUPS-Delete-Printer successful-ok
Printer "_tmp" deleted by "root".
REQUEST localhost - root "POST /admin/ HTTP/1.1" 200 149 CUPS-Delete-Printer successful-ok
Now, I’ve never seen this before, and I’m wondering if someone knows what’s possibly causing this. I’m using GNOME as my desktop environment, and I’m on NixOS unstable (b1b875982b17dabde9b4a37f3e229e74913e6db3). Cups is enabled just with services.printing.enable = true;.