-with two exceptions. These exceptions are imposed by the tool, not
-the library. A different client could impose different rules on the
-names of top-level code sections.
-
-The first exception we have already seen. A section name starting
-__Example:__ indicates code that is not to be included in the final product.
-
-The second exception is for the top level code sections which will be
-written to files. Again these are identified by their section name.
-This must start with __File:__ the following text (after optional
-spaces) will be used as a file name.
-
-Any section containing code that does not start __Example:__ or
-__File:__ must be included in some other section exactly once.
+with one exception. This exception is imposed by the
+tool, not the library. A different client could impose different
+rules on the names of top-level code sections.
+
+One example of the exception we have already seen. A section name
+starting __Example:__ indicates code that is not to be included in the
+final product. Any leading word will do, providing there is a space,
+and the first space is preceded by a colon, that section name will be
+ignored.
+
+A special case of this exception exists for the leading word
+__File__. These sections are the top level code sections and they
+will be written to the named file. Thus a section named
+__File: foo__ should not be referenced by another section, and its
+contents after all references are expanded will be written to the file
+__foo__.
+
+Any section containing code that does not start __Word:__
+must be included in some other section exactly once.