The gridfs module serves files out of MongoDB's GridFS, where a file is a
record and a row of chunks.  A location maps the request to a file by name
or by object id, answers a byte range out of the chunks it needs instead of
reading the whole file, and takes the content type, the ETag and the
Last-Modified from the file's own record.

This port only installs the module sources.  The module itself is built by
the nginx ports when their GRIDFS option is enabled.