is this based on some distro?
Libre Software
"Libre software" means software that respects users' freedom and community. Roughly, it means that the users have the freedom to run, copy, distribute, study, change and improve the software.
In particular, four freedoms define Free Software:
The freedom to run the program, for any purpose.
Placing restrictions on the use of Free Software, such as time ("30 days trial period", "license expires January 1st, 2004") purpose ("permission granted for research and non-commercial use", "may not be used for benchmarking") or geographic area ("must not be used in country X") makes a program non-free.
The freedom to study how the program works, and adapt it to your needs.
Placing legal or practical restrictions on the comprehension or modification of a program, such as mandatory purchase of special licenses, signing of a Non-Disclosure-Agreement (NDA) or - for programming languages that have multiple forms or representation - making the preferred human way of comprehending and editing a program ("source code") inaccessible also makes it proprietary (non-free). Without the freedom to modify a program, people will remain at the mercy of a single vendor.
The freedom to redistribute copies so you can help your neighbor.
Software can be copied/distributed at virtually no cost. If you are not allowed to give a program to a person in need, that makes a program non-free. This can be done for a charge, if you so choose.
The freedom to improve the program, and release your improvements to the public, so that the whole community benefits.
Not everyone is an equally good programmer in all fields. Some people don't know how to program at all. This freedom allows those who do not have the time or skills to solve a problem to indirectly access the freedom to modify. This can be done for a charge.
So I'm assuming that this is basically a custom themed Linux with WINE preinstalled?
Yes, something like this. I think it's a nice gag for Linux user.
If I'm being honest, I hate the Windows GUI design so the theme really doesn't do it for me. And WINE is easy to install on most major distros, so I would just recommend using one of those. Arch (or derivatives), Fedora, openSUSE and Pop! OS are all very good for desktop use.
So I've been playing around with the "Windows 11" version in a VM, and while it definitely still isn't for me, I am impressed by the effort to recreate the Windows look and feel. The Windows-like UI elements, especially animations and transitions, do feel kind of glitchy at times, but it's still clear that they made a genuine effort to replicate it instead of just throwing something together and calling it "Windows" (like this weird low effort distro that got some attention a few years back), so I really do have to give them credit. They also have some (presumably) custom tools to go with WINE including a script which automatically installs many of the common Windows dependencies like the .NET Framework, which could be useful as you don't have to hunt down those EXEs from Microsoft.
After all, WindowsFX shows the potential of Linux
I also remember this one http://www.windows93.net 😂
I kinda feel like why would anyone want to use this when they can just download a free copy of Windows 10 and be happy with that?
.The reason is, it's not Windows, it's Linux with all the advatages it has for a Linux user. Much better etter than ReactOS, a Windows XP fork attempt, which remains in beta after 10 years and as insider joke in Microsoft.