The XSLT Working Group has published a Proposed Recommendation of XSL Transformations (XSLT) Version 3.0. This specification defines the syntax and semantics of XSLT 3.0, a language designed primarily for transforming XML documents into other XML documents. XSLT 3.0 is a revised version of the XSLT 2.0 Recommendation published on 23 January 2007. The primary purpose of the changes in this version of the language is to enable transformations to be performed in streaming mode, where neither the source document nor the result document is ever held in memory in its entirety. Another important aim is to improve the modularity of large stylesheets, allowing stylesheets to be developed from independently-developed components with a high level of software engineering robustness. Comments are welcome through 19 May.