alt Hacker NewsTurtle WoW was also porting their fork to Unreal Engine 5 [1] but that got cancelled ~6 months ago due to a Blizzard lawsuit.
For anyone unfamiliar with WoW, private servers have been a thing for most of WoW's history. It's unclear to me where the source code came from. I've heard different stories (eg from Chinese servers) and also that it was a greenfield development reverse-engineered from the client. All of this was a copyright violation of course and Blizzard have shut down such servers in waves.
WoW originally released in 2004 and has changed every ~2 years with an expansion and the game now is vastly different to what it was originally, which is now called "vanilla". In the 2010s there was a lot of people calling for what became "classic WoW". Most private servers used an early version of the game (either vanilla or one of the first 2 expansions). A lot of people argued that game was more fun at that time and all the changes since have made the game worse.
This issue just didn't die and the game director was famously asked (by a still unidifentied fan AFAIK) if there were any plans to re-release the original game and he famously responded with "you think you do but you don't" at Blizzcon 2013 [2].
This just wouldn't die. There was one particularly famous private server called Nostalrius that got shut down by Blizzard but Blizzard ended up bringing that team in and by 2017, Blizzard announced Classic WoW [3], which launched in 2019 and for several years seemed to have more players than the current version of the game (called "retail") although that's tapered off now.
So Turtle WoW fit into a long history of wanting to play the original game. There's also a movement called "Classic+", which is to fork from the vanilla version of the game and make changes from that. Turtle WoW probably fit into the Classic+ model.
[1]: https://turtlecraft.gg/remastered