Looks like your sink was imported from Europe.
They have overflows on their kitchen sinks we do not have them here.
There is a reason we do not have them but I cannot remember for the life of me for What it is.
Best bet would be to try to contact the sink manufacturer. Kitchen sink should have manufactures name stamped on it somewhere
I believe bacteria billed up in the overflow is the issue. If your job/home is being inspected a lot of European and other import products such as the one you are showing may not be a certified product. In which case the inspector may not allow you to pass plumbing inspection as long as said product is still installed.