Make sure you are not blocking content.

https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop also see https://blog.mozilla.org/security/2021/03/23/introducing-smartblock/

https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection

Diagnose Firefox issues using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

What content is in the files if you open them in a file viewing utility for inspection ?

Is that an error page ?

I tried turning off enhanced tracking protection, but that didn’t help. I’m don’t think SmartBlock is to blame since I see that was introduced in Firefox 87 and this problem only arose since 93 I believe. In any case I tried changing extensions.webcompat.enable_shims to false but it didn’t help. I tried running Firefox in troubleshooting mode, but that had no effect. Of course before I wrote I tried deleting all cookies and history and restarting Firefox. I think the important detail is that this only happens with the .gz download, not the .zip or the uncompressed file. The download itself is an SQL database. I tried it with many databases. A typical example is for a database with 150 or so tables only the first table is in the file. I already mentioned this problem does not occur with Edge. I’ve since also checked with Vivaldi, which also works fine.

Boot the computer in Windows Safe mode with network support to see if that has effect in case security software is causing problems.

• https://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• https://www.digitalcitizen.life/4-ways-boot-safe-mode-windows-10/