Operator 2026-10-01: today Documents/View/ shows metadata only and Download streams the bytes; no file content is rendered as a page. SharePoint: Office Web Apps / WOPI discovery XML (app, action name=view|edit, ext, urlsrc) plus the XML Viewer web part (XSLT over an XML file). Declare viewers as data in WOPI discovery shape; a .mm file opens as a mind map (BRAINSTORM.4c). Ask-first on the discovery part shape.