/usr/lib/python2.7/dist-packages/csb/test/data/struct.ali.mfasta is in python-csb 1.2.3+dfsg-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 | >3p1uB
ENPDKPTDDV-NYNMNEPRLASTLR--G
>1d3zA
EV-EPS-DTIENVK------AKIQDKEG
|