This extension is to support the use of payment tokens with payment processors. It contains the part of token handling that I think core would ideally do & I will be adding to it. Currently it
1) creates a table civicrm_payment_tokens
2) exposes the table to views if you have civicrm_entity installed (Drupal only) by implementing the paymenttokens_civicrm_alter_drupal_entities & paymenttokens_civicrm_alter_drupal_entity_labels hooks
3) adds api crud to store payment tokens
4) adds an api function 'query' that attempts iterates through the tokens and for each calls the relevant payment processors api e.g
civicrm_api3('eway', 'tokenquery', array('contribution_recur_id' => x));
and saves that information into the token table. This allows payment processors to add a function for querying tokens (e.g to find out when they expire) without worrying about how to store it.
I used the fields from the equivalent table in IATS but didn't add contribution_recur_id as I wasn't sure about a 1-to-1 ration.
I hope to in the future at to this api jobs around processing scheduled payments & ability to use a saved token to pay on a contribution page in a processor agnostic way