New and updated styles automatically become "Additional" styles and will have "(dev)" appended to their titles. Do not append "(dev)" manually.
New styles should use URIs in the <id> element of the form http://www.zotero.org/styles/style-name, without an extension. The filename itself should be style-name.csl.
Manually modifying the value of the <updated> element is not necessary. A new timestamp will be generated automatically.
After committing a style, start a new Import/Export thread in the Zotero forums asking for feedback and pointing users to this page.