Here is the command I entered, which at first appeared to work:
$ libreoffice --headless --convert-to pdf example.odm
convert /home/zerubbabel/Documents/Books/Example/example.odm → /home/zerubbabel/Documents/Books/Example/example.pdf using filter : writer_globaldocument_pdf_Export
However, when I open the resulting pdf file, it does not include the subdocuments linked into the Master document. That is because when you open a Master document interactively, it first asks you, “Would you like to change the document, and update all links to get the most recent data?” and apparently the default answer is “No” rather than “Yes”, so it doesn’t import the linked subdocuments before generating the pdf.
So how can I make it default to “Yes” instead of “No”?