https://www.curseforge.com/minecraft/mc-mods/immersive-portals-for-forge
The Forge version is being provided but not supported. Only the Fabric version(https://github.com/qouteall/ImmersivePortalsMod) is still being supported.
The most code is remapped from the Fabric version(https://github.com/qouteall/ImmersivePortalsMod)
gradlew genIntellijRuns or gradlew genEclipseRuns