Advanced Fluid Handling used to ship the Space Exploration valve items, and removing them upstream leaves its own valve entities pointing at prototypes that no longer exist, which stops Factorio during loading. This patch recreates them.
Two smaller things come with it. Fluid handling buildings from every mod are collected onto the Advanced Fluid Handling tab instead of being split across two. And when Configurable Valves is installed, the Advanced Fluid Handling valves are hidden rather than offered alongside it, without removing the prototypes, so saves that already use them keep working.
Nothing else is touched, and the mod does nothing unless Advanced Fluid Handling is active.