/var/lib/pcp/config/pmchart/Netpackets is in pcp-gui 1.5.11.
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 | #kmchart
version 1
chart title "Network Interface Packets [%h]" style stacking
plot legend "in %i" metric network.interface.in.packets not-matching "^lo|^sl|^sit|^gif|^stf|^wlt|^vmnet|^MS TCP Loopback interface"
plot legend "out %i" metric network.interface.out.packets not-matching "^lo|^sl|^sit|^gif|^stf|^wlt|^vmnet|^MS TCP Loopback interface"
|