What are these messages called Rust sends into the global when the excavator gets activated or a heli comes?
And is there a plugin or a server command to remove these?

What are the messages ?

The ones that announce that the excavator has been activated or the patrol heli comes or that the oilrig is online now.
Those that Facepunch implemented last year within an update.

Merged post

Think I got it. https://umod.org/plugins/event-tips-remover