sendFile : the user can access the file of an instance, and a given rendition. This is used to restrict asset thumbnail visualisation rendition for a connected / unconnected user.
For example, the following rule will only render the asset preview of “public” assets to non-connected users (public being a metadata set to 1)
ISEXISTFIELD(objectname, 'public') AND object.public = 1 AND ( typeOp='variation' and STARTSWITH(subTypeOp, 'thumbnail'))