Not your side project.

Others also seem confused— it clearly wasn't the best wording. Maybe the usage is more common in my regional dialect or something.

'Workaday' technically has two definitions: the first is something work related, and the second is something ordinary, common, or routine. Both definitions carry connotations of the other though. In this context, I'm referring to the everyday code that we write to solve most problems. I'd juxtapose this with unusual code working around really weird constraints or making up for a fundamental shortcoming or bug in a language or critical library which might require janky counterintuitive code.