F9686 - partly revert download filename sanitize

Documentation/Manual.rst

@@ -7029,7 +7029,7 @@ Column: _savePdf
 Generated PDFs can be stored directly on the server with this functionality. The link query consists of the following parameters:
 * One or more element sources (such as `F:`, `U:`, `p:`, see download-parameter-files_), including possible wkhtmltopdf parameters
-* The export filename and path as `d:` - for security reasons, this path has to start with *fileadmin/*
+* The export filename and path as `d:` - for security reasons, this path has to start with *fileadmin/* and end with *.pdf*.
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