/usr/share/libwacom/isdv4-ef.tablet is in libwacom-common 0.18-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 | # this is for the Wacom pen as found in a limited special Tablet PC edition
[Device]
Name=Wacom ISDv4 EF
DeviceMatch=usb:056a:00ef
Class=ISDV4
IntegratedIn=Display;System
[Features]
Stylus=true
Buttons=0
|