Default unit millimeters when opening SVG files not pixels?

Just picking this back up in 2025 for anyone else frustrated with this. It was undoubidly the case that when saving an AI file as an SVG the width and height of that SVG would be set in pixels regardess of the units of measurement used in the document, at some point in the last couple of years that changed, the units used in the document were matched in the SVG.

This is troublesome as a lot of third party apps only recognise pixels. For example I use SVG files for a CNC router and the firmware crashes if you use anything but pixels. Until today I have typically saved the SVG, opened it in TextEdit and then manually changed the width and height of the SVG to match the pixel values used in viewBox. 

As mentioned above, a helpful and quick solution to this is to right-click on the document rulers change the units to pixels and then export the SVG. Once saved, revert the rulers back to the working units. 

However, this feels hacky, I can't help but feel there should be an option within the SVG Options dialogue to "match the document units"  if left unchecked the SVG will use pixels. 

macOS Sequoia 15.4
Illustrator 29.4

There is no unit saved when you export an SVG. 

The last opened/created file or the last set unit in the Preferences is used when opening an SVG.