Rendered text cannot be assumed to equal the underlying text, unfortunately

How so? As i understand your point, this would mean we cannot trust GitHub enough to return the same content in git clone vs curl?

As an example, webfonts can make rendered text differ from the underlying text that ends up on your clipboard.

Sure, but doesn't this assume that you cannot the publisher anyway? So why would you not trust their homepage but trust their source-code

	▲	danielrmay 2 hours ago \| parent [-]
		[dead]

cybrox 3 hours ago | parent | prev [-]

Download and inspect it.