Downloading a database with GZIP compression from PhpMyAdmin returns uncompressed files

Describe the bug

Since version 94.0.2 of Mozilla Firefox (64 bit) for Windows 10 64 bit, exporting a database with GZIP compression from PhpMyAdmin results in an uncompressed text file.
I report this bug to PhpMyAdmin because the ticket "https://bugzilla.mozilla.org/show_bug.cgi?id=1755324" on Firefox guides me to think about a PhpMyAdmin bug.

To Reproduce

Steps to reproduce the behavior:

1. With "Mozilla Firefox" (version greater than or equal to 94.0.2, for example 97.0.1) go to 'https://demo.phpmyadmin.net/STABLE/'.
2. On "Username:" field, insert 'root'. Press 'Go'.
3. Click on a database (for example 'egzamin ') and then in the top bar click 'Export'.
4. On "Export method:" select "Custom - display all possible options".
5. On "Compression:" select "gzipped".
6. Click "Go" at the bottom right of the page.
7. Save the file and then read with notepad (with notepad++ is more easy), it is result in .SQL format and not in compressed GZIP format.

Expected behavior

The saved file must be a GZIP compressed .SQL file.

Server configuration

• Web server: "nginx/1.14.2" ("https://demo.phpmyadmin.net/STABLE/")
• PHP version: 7.4.27.
• phpMyAdmin version: 5.1.3 (Git revision: f27346c from STABLE branch).

Client configuration

• Browser: Mozilla Firefox 97.0.1
• Operating system: Windows 10 Pro 21H2 64 bit.

Additional context

As I indicated in "### Describe the bug", I report this bug to PhpMyAdmin because the ticket "https://bugzilla.mozilla.org/show_bug.cgi?id=1755324" on Firefox guides me to think about a PhpMyAdmin bug.
It is strange that with the previous versions of Mozilla Firefox 94.0.2 the export worked correctly.

Thanks.