Are maker packs considered mods for update purposes?

Hello, I have played sims for years, but have never used Mods for compatibility concerns. I have recently downloaded some of the free maker packs from the marketplace and just saw the message about uninstalling any mods before the June 30th update. 

Are maker packs and also I guess the creator kits considered mods. I am seeing mixed answers on the internet and am concerned as uninstalling, reinstalling before and after updates is one of the things I wanted to avoid. 

Any help with this question would be very appreciated. Thanks!