Includes a file into the output. The contents of the file is parsed by the Nucleus skin/template parser, so you can use skin/templatevars. (see phpinclude and include for other include options)
IncludeMode and IncludePrefix<%parsedinclude(filename)%> again. To avoid endless loops, the maximum depth level you can go is 3.all
<%parsedinclude(filename.txt)%> <%parsedinclude(/home/user/myself/filename.txt)%>