Anyone know what this 'hack_file' is under table-option?

Just logged onto my hosting account and went to the TABLES to clean some garbage from my tables, and came across ‘hack_file’ set to ‘yet’ under all PP themes I use. You may go to your hosting cp-panel/phpmyadmin and navigate to your tables. Select one of your tables and you will see (yourtable_name)_options. Click on the click on that option. There is ‘hack_file’ set to ‘yes’. Is this something normal/default wp setting? Is anyone aware of this this file?

Thanks
g