Minecraft wiki entry for Development_versions, associated text: MC-185019 – Worldgen settings with empty structures parameter generates all structures extremely frequently.
MC-189788 – Certain mobs in boats sometimes take drowning damage while the boat is moving.
MC-190559 – Baby striders do not die when it is raining and they are in lava.
MC-190875 – Creating a custom superflat world with a structure that cannot generate in a given biome, then running /locate on that structure, softlocks the game.
MC-191031 – Players in spectator mode can interact with boats.