Fuckers. I don't know why you'd want to hack the IA, but they're dicks for doing so. I'm gonna throw some of my spondulix to the IA, and I'd encourage others to do so.
Spondulix is 19th-century slang for money or cash, more specifically a reasonable amount of spending money. Spondulicks, spondoolicks, spondulacks, spondulics, and spondoolics are alternative spellings, and spondoolies is a modern variant.
The only reason I can think of to get that data is to circumvent archive.org's limitations on renting out stuff so your bots can slurp books without getting throttled.
That is, my best guess is that this was pirates seeing if they can't add to libgen.