What’s this next to the fuse box?

Very annoying, indeed! And if you think it is annoying now, you should hear it when the dome light switches start getting faulty and it makes weak intermittent ground. Sounds like someone torturing a bumble bee under the dash.
But it will help prevent the embaressment of leaving the keys in the ignition and locking yourself out! LOL.
That must have been implemented after they got rid of the 'must use key to lock the door' configuration.
Although if it was there, I don't remember it working on my '75.
Fortunately I only did dumber things like lock my keys in the trunk. LOL. But getting them out I could solve on my own. :)