That's a lot of ®, curious how ClickHouse® Inc. is treating the use of its name by others ... Hopes it's not like Oracle with JavaScript

They sell managed ClickHouse so I suspect it’s a precaution

It's defensive language for sure, i don't know how much it adds of protection in reality, but i nonethelesss sympathize with the author if he feels the need to protect himself that way or signaling the risk he takes.