Borders with double thin lines convert to single thin lines.

edit

If you export to PDF and put zoom to 1600% the space between the double lines can be seen.

The file content.xml said: style:border-line-width-left="0.02mm 0.04mm 0.02mm, that is 0.08 mm, or nearly 0.23 pt.

Printing 0.08 mm at 300 dpi will leave a 0.94 dot for both lines (and space).

EDIT: Setting line width to 9pt (the maximum) these are the values in content.xml.

EDIT 2: Setting the line width to 6pt and 3pt bring some surprises: the proportions of double and thin-thick medium gap remains the same.

See edited source file (border line styles.odt).

Tested with LibreOffice 6.4.7.2 (x86); OS: Windows 6.1.

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