The command-line tools are provided by sumatrapdf-tool, which is installed next to SumatraPDF.exe. They only work after SumatraPDF has been installed.
Available in pre-release 3.7
Usage: sumatrapdf-tool pages [options] file.pdf [pages]
pages lists the box dimensions (MediaBox, CropBox, TrimBox etc.), rotation and UserUnit for each page, in XML format. The output looks like:
<page pagenum="1">
<MediaBox l="0" b="0" r="595.28" t="841.89" />
<CropBox l="85.0394" b="109.134" r="510.241" t="732.756" />
<TrimBox l="113.386" b="137.48" r="481.894" t="704.41" />
<Rotate v="0" />
</page>
If you don’t supply a pages list, all pages are shown.

All options #

Usage: SumatraPDF pages [options] file.pdf [pages]
  -p -    password for decryption
  pages   comma separated list of page numbers and ranges