/usr/src/gcc-5/debian/libasan.symbols.64 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 4 5 6 7 8 | __interceptor_shmctl@Base 4.9
_ZdaPvm@Base 5
_ZdlPvm@Base 5
_Znam@Base 4.8
_ZnamRKSt9nothrow_t@Base 4.8
_Znwm@Base 4.8
_ZnwmRKSt9nothrow_t@Base 4.8
shmctl@Base 4.9
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