/usr/lib/pd/extra/rtc/lb.pd is in pd-rtclib 4.1-2.
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 | #N canvas 63 44 388 264 10;
#X obj 61 97 outlet;
#X obj 61 23 loadbang;
#X obj 61 48 list append \$1;
#X msg 61 76 \$1;
#X connect 1 0 2 0;
#X connect 2 0 3 0;
#X connect 3 0 0 0;
|