I just had a look though all the about: pages and the only ones with lots of content are about:credits and about:licence which arguably serve a different purpose. Although the current page, chrome://ubiquity/content/confirm-add-command.html, is quite long as it is. My point was that by simply using the existing dark grey page background and putting those three 'zones' in your mock-up into the rounded-corner box it would suddenly appear as a Firefox UI page over a generic web page and I think this remains true regardless of the size of the page.

I personally like learn but believe it's a bit confusing… is the user doing the learning or is Ubiquity learning? I do believe the "subscription" feature of feeds does work right now.

Alberto, re: the security model, I'm not the best one to answer this, but the "trust" aspect of these commands is definitely something that will need further scrutiny.

As we're personifying Ubiquity with the Ubiquibot, 'learn' seems the nicest verb to add commands, not least as subscribing implies future updates which I don't think Ubiquity currently offers (but am now doubting I am right…)

Also, I prefer the term "subscribe" to a command feed. It gives me a warm fuzzy feeling that any bugfixes on the commands will be updated automatically. … Of course, if this is not what happens, then "subscribe" is a terrible choice!

The page is so nice the user might forget the risks.

Mozilla, for instance, does not guarantee that the addons linked are safe, but they have been scrutinised by Mozilla and are also constantly being looked at by the wider Mozilla comunity.

Vulnerability perception would be diminuished if the command would be retrieved by a central repository. There, the page suggested, would be very contextualized.