Alyssa Ross reports:

  I was able to manually connect to the UK provider EE (which is not
  currently listed) using the following settings:

    APN: everywhere Username: eesecure Password: secure

  Also, EE was formed as a merger of T-Mobile and Orange, both of which are
  still in the list.

The data was pulled off EE web site, checked agains AOSP configuration:
https://android.googlesource.com/device/sample/+/master/etc/apns-full-conf.xml

https://gitlab.gnome.org/GNOME/mobile-broadband-provider-info/-/issues/12
https://gitlab.gnome.org/GNOME/mobile-broadband-provider-info/-/merge_requests/82