libapache2-mod-xsendfile - 0.12-2+b1 main

This package provides the xsendfile module for the Apache 2 webserver.
xsendfile is a small Apache2 module that processes X-SENDFILE header
sent by the original output handler.
.
If it encounters the presence of such header it will discard all output
and send the file specified by that header instead using Apache internals
including all optimizations like caching-headers and sendfile or mmap if
configured.
.
It is useful for processing script-output of e.g. php, perl or any cgi.