There is "spigot.yml" file with setting
unknown-command: ''

I want to disable a feedback for any unknown command so I put nothing between those two apostrophes. However, the game still gives me an empty line in respond.
But I don't need this empty line - I need nothing in respond. Just as "/gamerule sendCommandFeedback false" gives absolutely nothing in respond to existing commands (it doesn't give an empty line).

Please add a feature to completely disable any response to unknown commands.
Smth like
unknown-command: null
or
unknown-command: none
or
unknown-command respond: false