I don’t recall reviewing or discussing OpenAQ or AWS Glue in any of the previous lectures
AWS Glue is covered in AWS Certified Solution Architect – Associate. You should know that course and other associate courses inside out before taking this course. Also, the nature of Professional certifications are such to provide you only clues, and you are expected to Google Search, read AWS Service FAQ, etc. to familiarize yourself with concepts you haven’t heard of before.