$buffer = <get next chunk from file>
($out, $status) = $inflater->inflate($buffer);
# until status is Z_STREAM_END or other than Z_OK (meaning error).
# $out will have uncompressed (inflated) chunk.
It is probably significant that your data file is completely missing "\r" while having twice the statistical expected count of "\n". Thus it is unlikely that simple unflattening will do the trick. The data seems to be additionally processed in some way. maybe this irregularity can give some hints. 😉