when file associations (and protocol associations)

When are file associations going to be available?
And protocol associations (celestia uses celurl's which have the form: cel:\\* )?

I'm asking this because there is nothing mentioned about it in the portableapps format specification:
https://portableapps.com/development/portableapps.com_format

A File Associations tab is visible on one of the screen shots on this page:
https://portableapps.com/node/24104

When are file associations going to be added in the specification?