Update: Arbital Scrape V2
I've scraped http://arbital.com as the site is unusably slow and hard to search for me.
The scrape is locally browsable and plain HTML save for MathJax.
https://drive.google.com/open?id=1b7dKhOzfMpFwngAeI8efeOzv147Lv_mx
https://emma-borhanian.github.io/arbital-scrape/
If there's interest let me know as I may tidy up and open source my code. edit: working on this

Mirror: www.obormot.net/arbital
Nice project thanks. It's also consistent with my analysis that Arbital's fancy wiki features never added much value (say, more than +30%) beyond the value that that content would have if published in a pre-existing format and venue.