Inside the game, there is a prop called the Wordless Heavenbook, where you can see each update
My machine translation may not be accurate enough

If you craft the Myth Worlds book under the myth tab (It should cost 2 papyrus), then set it on fire using a torch, you should get a readable 'Sealed Book'. This will show all of the current recipes in the mod, playable characters, as well as bosses/NPCs and how to summon them!

Currently, not everything has an English translation, so I usually take a screenshot and try to use an image translator to get an idea about what is being said.