if you put any file in .minecraft/server-resource-packs and join any server with required resourcepack the files that are inside, i found out about this the hard way, trying to modify server rersource pack root, but there are some people who are using unofficial launchers and like to keep all their files in on place and just create a symlink to original folder so if they want to have their server resource packs together with all the other resource packs, they will have to suffer the similar fate

Steps to reproduce

Put some very precious resourcepack into server_resourcepacks folder

launch the game and log onto the server which requires server resourcepack

What should have happened

Your precious resourcepack is safe and sound

What actually happens

You watch as your precious resourcepack is regarded as previous and is consequently deleted