5.4.1 is 2 years old.
MineClone2 very very likely needs an up-to-date version of minetest.
It makes sense that the content manager doesn’t show you stuff that isn’t compatible with your minetest version.
etit:
MineClone2 0.84.0 needs minetest 5.5.1+
The last/only MineClone2 version compatible with your minetest version is MineClone2 0.76.0, which is roughly a year old.