What problem does this address?

As far as I can tell, there is no way to hook into the LinkControl component and modify the query that fetches link suggestions. It would be really nice to have a setting/hook that allows us to do so. For example, if we wanted to block certain content types or pull in link suggestions from remote sources.

What is your proposed solution?

Add a filter to provide a different search handler or a different query to the the fetchSuggestions functionality in LinkControl