22877eb0__Services___O_Reilly_Broadcast_Table_3__Command_Pipes_Command
[Description] Taking a document and an XPath match expression, viewport applies it's sub-pipeline to each matched node and replaces the former with the latter, then returns the document in its entirety. [Command] 
viewport
XProc: Drupal, XML Pipelines and RESTful Services - O'Reilly Broadcast
Command