The “Files” preference pane allows you to configure certain features of MultiMarkdown Composer’s behavior.
“File line endings” — Choose the line endings used when saving MultiMarkdown text files. Default for Mac OS X is “\n”, but you can change this as necessary.
“Suggest better filenames for untitled documents” — if your document has “title” metadata, use that as the suggested filename when saving for the first time. If no “title” metadata is present, use the first 5 words of the document.