Security alert about changed file

Wordfence alerted me to some changes made to a file that are not the same as the one downloaded from the WordPress repository. Here are the comparisons. I did not edit this file so why is it different?
https://ibb.co/XVcVNsH
https://ibb.co/CWzy7db

• This topic was modified 6 years, 1 month ago by sleeplessindc. Reason: correct grammar