If you declared an optional activity with advanced print options via the NoType:android/R$attr;Href=../../../reference/android/R.attr.html#advancedPrintOptionsActivity attribute, this extra is used to pass in the currently constructed Android.Print.PrintJobInfo to your activity allowing you to modify it. After you are done, you must return the modified Android.Print.PrintJobInfo via the same extra.
You cannot modify the passed in Android.Print.PrintJobInfo directly, rather you should build another one using the NoType:android/print/PrintJobInfo$Builder;Href=../../../reference/android/print/PrintJobInfo.Builder.html class. You can specify any standard properties and add advanced, printer specific, ones via NoType:android/print/PrintJobInfo$Builder;Href=../../../reference/android/print/PrintJobInfo.Builder.html#putAdvancedOption(java.lang.String, java.lang.String) and NoType:android/print/PrintJobInfo$Builder;Href=../../../reference/android/print/PrintJobInfo.Builder.html#putAdvancedOption(java.lang.String, int). The advanced options are not interpreted by the system, they will not be visible to applications, and can only be accessed by your print service via PrintJob.GetAdvancedStringOption(string) and PrintJob.GetAdvancedIntOption(string).
If the advanced print options activity offers changes to the standard print options, you can get the current Android.Print.PrinterInfo using the PrintService.ExtraPrinterInfo extra which will allow you to present the user with UI options supported by the current printer. For example, if the current printer does not support a given media size, you should not offer it in the advanced print options UI.