/usr/share/kamailio/db_berkeley/kamailio/pdt is in kamailio-berkeley-modules 4.2.0-2+deb8u3.
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 | METADATA_COLUMNS
id(int) sdomain(str) prefix(str) domain(str)
METADATA_KEY
1
METADATA_READONLY
0
METADATA_LOGFLAGS
0
METADATA_DEFAULTS
NIL|NIL|NIL|''
|