I am using the module report_xls, the only documentation I could find of it is the one one in its __openerp__.py description, which suggests you to download the modules account_journal_report_xls and account_move_line_report_xls to see how it works, because those modules use it to export to Excel.

I was looking their codes for a long time and from other module which seems to use report_xls too, but I am not able to know the meaning of several lines. For example, account_journal_report_xls adds in the wizard a button to export, and this one calls a function which finally returns this:

return {
   'type': 'ir.actions.report.xml',
   'report_name': 'nov.account.journal.xls',
   'datas': datas,
}

The first item of the dictionary, 'type', is always the same ('ir.actions.report.xml') for every module. But I do not have any idea of which is the meaning of the other two items, 'report name', and 'datas'. Obviously I do not want to know what the module is exactly doing, only what are the meanings of those two fields, what I should write as 'report_name' and as 'datas'.