What characteristic distinguishes a private sector job supporting a public function (like IT maintenance for the state) from direct public employment?

Answer

The employer is a for-profit company operating via contract

A software engineer working for a private contractor performing IT maintenance for the state is technically in a private sector job, even though they perform a public function, affecting their benefits and career mobility.

What characteristic distinguishes a private sector job supporting a public function (like IT maintenance for the state) from direct public employment?
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