change date format in widget recent posts

I started a topic earlier (https://wordpress.org/support/topic/change-date-format-39/), and Denzel Chia was kind enough to add a request on Github. https://github.com/presscustomizr/hueman/issues/343

I just found out this issue has been set to ‘Fixed” 29 days ago by Nikeo, but I’m not quite sure what to do: should I add the file functions/widgets/alx-posts.php to my child theme and alter the date format there? Or is the option to change the date format for the recent posts widget hidden somewhere in the customizer?