Vested holiday days are last year's days you have not yet taken. The final year's pro-rata days are computed automatically and can never have been taken.
Every untaken vested holiday day counts twice: once as holiday pay and once as holiday allowance (article 245(1) and article 238(5)).
The headline figures are gross. The net shown removes the 11% Social Security share and any unserved notice, but not income tax, which depends on your bracket.
This calculation excludes the article 366.º dismissal severance, which exists only when the employer ends the contract for objective reasons and has its own calculator.