A
Welcome to Android Central! It has to do with system updates and mobile device management, most likely with how AT&T manages pushing system updates to the phone over-the-air: https://www.stigviewer.com/stig/lg_android_6.x/2016-05-05/finding/V-66861. (BTW, @VidJunky, in this case, I think DMS means Device Management Service or Download Management Service.)
Try not to assume everything you don't recognize is something malicious -- that'll just cause unnecessary anxiety. Is the phone behaving in some way that makes you worried you've been "hacked"?