PeerFactor 404 crawler

Stange hits

[DanA]

Is there any information about this user agent?
PeerFactor 404 crawler

[dcheney]

I've noticed it nibbling a bit on my site over the weekend - only a few random pages. All the hostnames are from "yellis.net".

[DanA]

Same hostname, it looked like it was grabbing random pages but it actually tested links from one page and used head requests, was redirected -as it was asking for pages containing the word email- and accepted to be redirected.