emacs has to know where your schema lives so that it can help you build and maintain a valid document. This is a two-stage process:
emacs has an internal
tells it all the places to search for schema
locating files. This variable's default
DIST-DIR is the distribution
schemas.xml file in the
distribution directory handles many of the common cases
such as XSLT files or DocBook documents.
You can also have a
file in the same directory as the document you are
working on. This file is also a schema locating file.
Each schema locating file specifies rules for
associating files with schemas. The rules can use the
file's extension (such as
the file's root element (such as
to infer the correct schema. If all else fails, it can
simply specify file
When emacs opens your file, it looks through the schema locating files in order until it finds a match.