Compared to its later main sequence life, how does the total energy release of a low-mass star's contraction phase compare per unit mass?

Answer

It often releases a greater total amount of energy per unit mass

The pre-main-sequence contraction phase, although shorter, often releases a greater total amount of energy per unit mass due to the intensity of gravitational energy release when the radius is large.

Compared to its later main sequence life, how does the total energy release of a low-mass star's contraction phase compare per unit mass?
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