Why is "GPLayout" (parameter data type) not documented for Arcpy toolboxes?

[JoshMakesMaps]

I was playing around with toolboxes a while back and found that "GPLayout" is accepted as a data type parameter. It works for my needs surprisingly.

Just curious why it's not listed in the documentation. Is this data type safe to use if it's not listed here?

Thanks!

P.S.

Is there an alternative method to get a list of layouts, other than using this data type as I did in the screenshot? Just wondering how other people accomplish this.

ArcGIS Pro 3.0.2