Hi,

I notice that fetch:content-type()[1] returns "application/octet-stream" for files with the commonly used XProc file extensions *.xpl and *.xproc.
This seems to be driven from the list in src/main/resources/media-types.properties [2]
Would it be possible to add these extensions as "application/xproc+xml" or add a mechanism to allow extension/customisation? Maybe similar to [3]

For static files served from jetty adding mime-mapping elements to web.xml works [4]

[1] http://docs.basex.org/wiki/Fetch_Module#fetch:content-type
[2] https://github.com/BaseXdb/basex/blob/master/basex-core/src/main/resources/media-types.properties
[3] http://docs.oracle.com/javase/7/docs/api/javax/activation/MimetypesFileTypeMap.html
[4] https://stackoverflow.com/questions/33803109/how-can-i-set-mime-mapping-to-a-file-served-as-static-content-by-jetty-runner/33809187#33809187