ThrowableProjectile
Link to throwableprojectile
Importing the class
Link to importing-the-class
It might be required for you to import the package if you encounter any issues (like casting an Array), so better be safe than sorry and add the import at the very top of the file.
ZenScript Copyimport crafttweaker.api.entity.type.projectile.ThrowableProjectile;
Extending Projectile
Link to extending-projectile
ThrowableProjectile extends Projectile. That means all methods available in Projectile are also available in ThrowableProjectile