I've created composer.json files for my modules and added them to packagist.org I noticed that they have been included on http://addons.silverstripe.org/ with a profile automatically created at http://addons.silverstripe.org/authors/259.
I've added an avatar to github, which has been included, but I noticed that some authors also have a link to their website ( addons.silverstripe.org/authors/310 ). How / where does this come from? And is it also possible to add a short bio or other info?