Who runs it
Perplexity. It names itself with the token PerplexityBot.
What it does
It is designed to surface and link websites in search results on Perplexity. Perplexity says it is not used to crawl content for AI foundation models.
Renders JavaScript
Not yet observed. Perplexity doesn't say whether PerplexityBot runs scripts, and this site hasn't recorded a verified visit yet.
How to verify it
Match the visiting address against Perplexity's published list, and combine that with user agent matching, as Perplexity recommends. Perplexity documents no reverse DNS check.
robots.txt
The PerplexityBot token controls it, and Perplexity recommends allowing it in robots.txt. Perplexity doesn't state outright that it obeys robots.txt.
Questions
Is Perplexity-User the same machine?
No. Perplexity-User fetches a page when someone asks Perplexity, and Perplexity says it generally ignores robots.txt rules.
docs.perplexity.ai/guides/bots