Upgrading SMS User

I am in the process of upgrading the SMS User module to D7 and wanted some feedback and also had some questions.

So my questions are as follows:
1. Is there a design doc for the SMS User module I should follow? If not...
2. Why are there two stages of registration through sms, or is this just for when the user adds the number to their currently existing user? (Pending/confirmed)
3. Why was the login metadata needed?

Also, don't forget about the feedback, i.e. features you would like seen.

SMS Framework

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