Adds glass slabs according to crafting recipes for other slabs, as well as glass walls in place of vertical slabs. Apparently no other mods are available to provide this for 1.14.4 without requiring Fabric.
This is an amateur mod built with MCreator. It's extremely low-effort, but should also be very lightweight.
Todo: If anyone knows how to make vertical slabs in MCreator, please let me know and I will add them in addition to glass walls. Until then, this will be considered complete with only horizontal slabs and walls.