Having worked in aerospace, and seen how some of the more "specialty" metal alloys corrode, I concur with the NASA interpretation that these images of the inside of the rover are consistent with salt contamination and corrosion.
It's not NASA's interpretation, though. The references to NASA's abiotic hypotheses are all about the (probably) hematite nodules.
The primary author on this -- who is, I note, retired from a research institute that, so far as I can tell, has never actually existed -- is just miffed that nobody cared that he made Martian maybe-fungus Pinterest out of the NASA/JPL rover photos and invited a bunch of random geologists/biologists to rate how likely it is that a bunch of random photos show things that might be fungus, so he's decided to play to the lay crowd with an open-access jumble of literature references, pseudoscience, and insinuations that NASA is wrong. (le gasp!) It's written to look and sound like a paper if you don't look too closely, and it references actual papers so we can talk about the actual science it mentions, but there's a reason that it's in a "journal" with no listed impact factor currently soliciting articles on such worthy topics as:
-SpaceX and Tourists on Mars: Good or Bad for Science?
-Ancient Greece/Rome, Culture, the Trojan War, Mars
-Is Life on Mars Contrary to Torah, the Bible, Islam, Taoism, Buddhism, Hinduism...
And don't forget their future edition on "-The Expanding, Collapsing, Anti-Matter, Parallel Universes"
The more you look into their site the better it gets. They're not focused on primary research, they've got reprints of slightly less farcical journal articles, Amazon ads in the margins and literally every paper I check references the same guy. This is a pseudoscience gold mine.