What is product debt you ask?
It’s the cause of your sleepless nights, missed deadlines and laggy website performance. The root of all that is evil in your professional existence. It’s a ticking time bomb inside your company that you, Mr. or Mrs. Expert Product Manager have to defuse, that’s what it is.

OK, I am being a we bit emphatic, but I am attempting to make a point.
Each feature of a product comes with a certain amount of collateral costs beyond simple development. These collateral/overhead costs include quality assurance, operations, documentation and many other areas of your organization.
Like all debt, product debt accrues silently as product features are iteratively added and modified. While in most organizations, product debt gets lumped in with technical debt as development teams need to make technical compromises in order to work around software code limitations in order to launch new features, product debt is actually the driver of technical debt.