[dotancohen]

Presumably the same way that Firefox makes an HTTP request to the webserver then formats the page for the human user. This is just formatting that page differently. This is no more a scraper than is Firefox's Reader Mode.

That said, lying about the UA is not cool.

[Animats]

I have something that sends a UA of "Sitetruth.com site rating system". Many sites won't talk to that.

[_heimdall]

I've used a reader mode library that I think as created by Mozilla and handles converting a site to reader mode locally. Does the Firefox browser do it locally, or at least on demand? If so I wouldn't really consider that scraping since they aren't parsing the site and storing data for later use.