What is Budget to Date Field on the Manage Project Budget

Summary:

What is Budget to Date Field on the Manage Project Budget; It shows an amount that is differnt everytime on different projects and for this example it shows zero.

Content (required):

Create Project and Budget with Lumpsum amount and Post actuals. When queried the Project Budget, it shows the Budget to Date as Zero? whats the formula of this field?

Version (include the version you are using, if applicable):

23A

Code Snippet (add any code snippets that support your topic, if applicable):