https://bugs.winehq.org/show_bug.cgi?id=54259
--- Comment #5 from Jürgen Luers juergen@luers-net.de --- I retested it today. The problem is gone. Now I get identical files without a warning from Firefox. I haven't changed anything and wanted to search for the problem.
Firefox debugger still shows, that the link points to //dl.winehq.org/wine/source/8.0/wine-8.0-rc2.tar.xz, but it results in the same file. md5sum is correct.
My Firefox version still is 108.0.1. Something must have changed on winehq website. From my perspective, the problem is solved.