From here and here it is clear that fedora 42 has not suddenly switched to XFCE as the default.
Yet the official fedora 42 announcement page says that XFCE (fedora-42-xfce) is the default and the GNOME version (fedora-42) is “alternative.”
This was posted several months ago. It should be corrected, or something should be posted here explaining why XFCE is suddenly the main version.
I agree, this has never made sense to me. For years Qubes installation has defaulted to a fedora XFCE setup but the naming made the gnome one seem like the default one (including the upgrade news release and install instructions making it confusing)
This link illustrates the confusion, it acts like installing fedora xfce is a alternative action and the cli used is the old one whereas the gnome one is the new qvm-template install one. I had hoped the docs migration would resolve this confusion but it didn’t, making me think that there’s some reasoning that I’m missing.
There was a vote to make XFCE the default in Qubes OS
Following the github issue related to the change, you will get some answers to your “why ?”.
About this: the docs migration was only a conversion from one platform and markup to another. No major content change occurred. There is still a lot of pages that could be updated.