Unusual End's V1.0.8 added the Ancient Shard, a green shard used to craft the Ender Respawn Altar, a block really similar to the End Portal Frame. So, it can finally explain what the End Portal is made of, but then, why not making us able to obtain it if we can get Ancient Shards ?
This need to be used with this mod : https://www.curseforge.com/minecraft/mc-mods/unusual-end
That's why I created this datapack to complete my End mod. It will add a recipe for the End Portal Frames, using 3 End Stone, 2 Ancient Shards and 1 Wandering Pearl by Frame (The Wandering Pearl is an item from Unusual End, made using 8 Chorus Fruits and 1 Ender Pearl). I don't consider it "too op", as you need 24 Ancient Shards to create a full portal, and Ancient Shards are really really rare items, only found in ancient cities chests, it's a super end-game craft, and being able to create End Portal isn't a real problem at this level of progression.
You can add this datapack to your modpack