/usr/share/gdb/syscalls/gdb-syscalls.dtd is in gdb 7.11-0ubuntu1.
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 11 12 13 14 | <!-- Copyright (C) 2009-2016 Free Software Foundation, Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved. -->
<!-- The root element of a syscall info is <syscalls-info>. -->
<!ELEMENT syscalls-info (syscall*)>
<!ELEMENT syscall EMPTY>
<!ATTLIST syscall
name CDATA #REQUIRED
number CDATA #REQUIRED>
|