Legacy support, basically. You're hired to maintain some key legacy monster created by people long since fired, and there is no option of refactoring it due to sunk cost fallacy by the business.

So, you're stuck just doing nothing but little "keep the lights on" tasks, your only job is to keep the buggy mess running, and you have little-to-no opportunities to modernize or do any best practices due to the limitations of the legacy monster and total lack of interest on the business-side.