klusark/residual — comment on commit efd6c7bd78564647890d69f9cc19c7d03e31a070
File:  line 0
By klusark:

I don't think so. wrapCompressedReadStream does:

bool isCompressed = (header == 0x1F8B || ((header & 0x0F00) == 0x0800 && header % 31 == 0));