/usr/lib/pd/extra/jmmmp/appent-help.pd is in pd-jmmmp 0.1.1-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | #N canvas 329 129 450 300 10;
#X obj 189 121 appent;
#X text 73 61 [list append]--[list trim] shortcut;
|