Description of problem:

When using the `file -i` command or the file library (more details on that case here: [0]), for some gzip files and not others, the result seems to be incorrect, even though the gzip file has a valid "magic number" identifier value just like any other.

[0] https://github.com/rpm-software-management/createrepo_c/issues/353

Version-Release number of selected component (if applicable):

From RHEL 8 until recent versions of Fedora. I haven't tested RHEL 7 or 9 specifically.

How reproducible: Very

Steps to Reproduce:

Take the attached gzip file, run file -i af12533499469117e3824bc938bfc3208539deb44bbf56ec2612fc383b28a1f4-primary.xml.gz

Actual results:

The response "application/octet-stream; charset=binary" is incorrect. A second person tried to reproduce this on Fedora 39 (rawhide) and got a different incorrect result:

$ file af12533499469117e3824bc938bfc3208539deb44bbf56ec2612fc383b28a1f4-primary.xml.gz
af12533499469117e3824bc938bfc3208539deb44bbf56ec2612fc383b28a1f4-primary.xml.gz: DOS/MBR boot sector; partition 1 : ID=0x4b, active 0xd0, start-CHS (0x63,239,44), end-CHS (0x33d,134,0), startsector 316955931, 1708404748 sectors; partition 3 : ID=0x53, active 0xaa, start-CHS (0x33a,156,2), end-CHS (0x22c,176,51), startsector 1315648692, 2595702924 sectors; partition 4 : ID=0x3a, active 0xca, start-CHS (0x1d5,97,37), end-CHS (0x28b,241,55), startsector 2173204403, 2875341233 sectors
$ rpm -q file-libs
file-libs-5.44-3.fc39.x86_64

Expected results:

"application/gzip; charset=binary"