I never tested it but I could find world2minetest or alternatively:
Alternative 1 - OpenStreetMap + Real Terrain Mod
You could download heightmap from OpenStreetMap to use Real Terrain mod to generate it.
Alternative 2 - Use whatever tool to generate for Minecraft then convert from Minecraft into Luanti
You could use mcimport or MC2MT(Luanti forums thread)
For those who don't know what iLovePDF is, it basically allows you to convert a literal equal copy of PDF into docx or a format more suited towards editing on LibreOffice/OpenOffice and some other things related to PDF, rarely losing some visual formatting when it does its usually related to the font but its not so often
I assume you ask where in the Git mention the Flathub link since Flathub deems it unverified? It's on On Linux section of the ReadMe
Are there revese engineered open source version of the other games?