Let me clarify why; I frequently come across datasheets (eg to flash memory ICs) that have security enabled for some strange reason. Nothing secret, just plainly downloaded from the Internet. I can open, and print, but not highlight or add remarks.
Existing solutions I've found so far are inadequate since they typically are either 'download this obscure-sounding executable', 'upload and convert on this sketchy possibly-malware-injecting-website', or resort to printing the entire thing to a new pdf document (eg via PDF creator) - but this makes text un-highlightable.
I don't mind anything involving hex-editing, some node.js or python-lib, or chanting and dancing, as long as it gets the job done.
I just want to be able to highlight and copy text :(