This seems to be a version of the Tawain Constitution in Chinese.
I am not sure what "big5" format is, but it's likely it is designed
to be viewed under the free software available via anonymous FTP
from june.cs.washington.edu (also where these files came from)
under pub/Taipei-100/* which seems to be a system for Chinese
Wordprocessing for the Macintosh.

* NOTE: I have been informed that the constitution contained herein
is a DRAFT constitution and has no legal force.