Gross 1 salary is the amount most often negotiated by the employee with their employer. It is the amount stated in your employment contract and serves as the basis for all further calculations.
This amount directly belongs to the employee, but it does not sit entirely in the account, but mandatory contributions and taxes are settled from it. It includes:
Negotiating salary in gross amount is the standard due to various tax reliefs that workers may have (e.g., dependent family members, disability). Two workers with the same Gross 1 salary can have completely different Net salaries if they have different tax reliefs. That's why negotiating a gross amount is the only fair way to define the value of a workplace for the employer — regardless of the worker's private tax situation.