when (Jakarta Server Faces 2.3.2 VDL Documentation)

Description:

Subtag of <choose> that includes its body if its condition evalutes to 'true'

Attributes
Name	Required	Type	Description
`test`	`true`	`javax.el.ValueExpression` (must evaluate to `boolean`)	The test condition that determines whether or not the body content should be processed.

jstl-core