As a workaround, import your Mendeley metadata and documents into Zotero, then use the Calibre "Zotero Metadata Importer" plug-in to update Calibre with the (new) Zotero PDFs plus their metadata via the Zotero standard CSV export file.
The ZMI ToolTips are the "user instructions". You must install ZMI to read them.
The Original Post may be found at:
https://www.mobileread.com/forums/sho...d.php?t=275476
There are currently ~570 ZMI users.
DaltonST