How many blocks can an observer see?

How many blocks can an observer see? Observers should have a mode, where they detect block updates up to 8 blocks in distance, if there is a clear line of sight. “Clear line of sight” means, air or transparent blocks (glass, leaves, water, etc).

Observers should have a mode, where they detect block updates up to 8 blocks in distance, if there is a clear line of sight. “Clear line of sight” means, air or transparent blocks (glass, leaves, water, etc).