/usr/share/m17n/GB_1988-80.map is in m17n-db 1.6.5-1.
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 | # Generated from /usr/share/i18n/charmaps/GB_1988-80.gz
0x0000-0x0023 0x0000
0x0024 0x00A5
0x0025-0x007D 0x0025
0x007E 0x203E
0x007F 0x007F
|