Originally I met that issue in whonix-16-dvm with tor browser. Here in windows with firefox, I am able to upload a .cpio.gz file. Maybe it’s a tbb bug?
Edit: Interesting enough, I’m not able to reproduce the issue in all possible environments, including in whonix-16-dvm with tor browser, . Sorry for the disturbance.
However, there should be logs that a .cpiogz file had been uploaded in HCL - Lenovo Thinkbook 14 Gen3 ACL, although I didn’t post it because of privacy concerns.