Hi Stephen,

I can't be 100% sure based on this cropped view of the area but this looks like you've got a custom design or maybe even code applied to the program display so it's difficult for me to confidently narrow down the language string identifier for the 'Required' text.  I would start with the 'totara_program' component but you might want to search for the term 'Required' in your language pack across all components.  Have a look at the Customising site language video to see how you can find and change this string - assuming it's not hardcoded.

Cheers,
Meredith