/usr/lib/x86_64-linux-gnu/plplot5.10.0/driversd/tk.driver_info is in plplot-tcl 5.10.0+dfsg2-0.1ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
tk:Tcl/TK Window:1:tk:7:tk