This is exactly the case. I've done conversions before where it was possible to see and extract underlying, hidden elements, that were not visible or even dete

This is exactly the case. I've done conversions before where it was possible to see and extract underlying, hidden elements, that were not visible or even detectable in the rendered webpage in a browser. This is actually a somewhat common method when it comes to a bit of corporate sleuthing.. anytime you see a pretty website with vector-y graphics, maybe engineering-drawing representations.. if the data hasn't been stripped completely or redrawn you can extract information that otherwise people would assume unknowable. In a recent example... I did this on a startup company's page involving a product where they had a CAD-like side view drawing of one of their products... but the base file (in this case it was an SVG) driving the page actually contained multiple hidden views of the same product and other products and at the 'real' precision of what likely was a DXF export from a CAD program, given to the web team. This allowed a critical dimension of an unannounced product to be precisely determined (to three significant figures) which was a spec that had not been publicly released...