All GFWM multi-part uncompressed cab files aren't read/extracted properly at the moment. They're handled just fine by GNOME file-roller, 7z, and unrar. According to infoprint and 7z, they aren't compressed whatsoever.
Infoprint output:
info-2025-04-16_152108.2491.txt
7z output:
Path = F7FFF97B64A12E9B0A8C741670ADE8BC3A9DF5A9_F216DBA6-E510-499A-92BB-47C84AAC5BC3_1.cab
Type = Cab
WARNINGS:
There are data after the end of archive
Physical Size = 524288024
Tail Size = 6992
Total Physical Size = 16654768585
Method = None
Blocks = 42
Volumes = 32
Volume Index = 0
ID = 46538