can anyone explain in simple terms what does type! do ?

{
a!gridLayout(
label: "Customer Details for Loan Transaction",
labelPosition: "ABOVE",
headerCells: {
a!gridLayoutHeaderCell(label: "Customer Name"),
a!gridLayoutHeaderCell(label: "Customer Address"),
},
columnConfigs: {
a!gridLayoutColumnConfig(
width: "NARROW",
),
a!gridLayoutColumnConfig(
width: "NARROW",
),
},
rows: {
a!gridRowLayout(
contents: {
a!textField(
value: ri!customerDetails.name,
saveInto: ri!customerDetails.name,
),
a!textField(
value: ri!customerDetails.address,
saveInto:ri!customerDetails.address,
),
},
),
},
addRowLink: a!dynamicLink(
label: "add field",
value: 'type!{urn:com:appian:types:SSA}SSA_CustomerDetails'(),
saveInto: ri!customerDetails,
),
selectionSaveInto: {},
validations: {},
shadeAlternateRows: true
)
}

In the above expression, by clicking on Link, a new empty rows are added to grid, and type! plays a role in it, i'm still confused, how does type! will do it exactly?