Protocol handlers allow links like mailto:email@example.com to be handled by a webmail application. In order to do that, the site needs to support a special API described on https://developer.mozilla.org/en-US/docs/Web-based_protocol_handlers. For en-US, we're currently shipping with GMail and Yahoo! Mail for mailto:, 30boxes for webcal: and Mibbit for irc: urls. For Guarani, we'd like to do that, too. First, the localization team and flod (Francesco Lodolo) will look at the market for the language and come up with a good candidates. Huber, we'll need your input on this. The guidelines for making recommendations are on <https://wiki.mozilla.org/L10n:Firefox/Productization>. Following that, the evangelism team reaches out to try to get the vendor to support protocol handlers. http://people.mozilla.org/~ctalbert/ has test cases for mailto:. Once that happens, flod will take over the actual implementation, which will need to change the gecko.handlerService.* entries in browser/chrome/browser-region/region.properties. Please don't make changes to that file without getting a positive review by flod or somebody else appointed by flod/Stas on a patch for that change upfront. The Guarani team and flod will be driving this bug to completion.
I agree with you. The default configuration for Firefox in this Matter will be ok for Firefox in Guarani. Gmail, Hotmail and Yahoo are the most popular (the people use these tools in spanish)