/usr/src/gcc-5/debian/lib32objc4.symbols is in gcc-5-source 5.3.1-14ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | libobjc.so.4 lib32objc4 #MINVER#
#include "libobjc4.symbols.common"
__gnu_objc_personality_v0@Base 4.2.1
|