Please delete all my D6 and D7 follows from the core queue

This quick reversal of project_issue_flag_issue() looks like it is working for individual issues:

$account = user_load(9446);
$node = node_load(481000);
$flag_name = project_issue_get_follow_flag($node);

if (!empty($flag_name) && is_object($account) && $account->uid != 0) {
  $flag = flag_get_flag($flag_name);
  if ($flag->is_flagged($node->nid, $account->uid)) {
    $flag->flag('unflag', $node->nid, $account);
  }
}

I unfollowed a couple, and I think can get the rest tomorrow.

I don't think this is the same as #1093650: Provide VBO support for issue management. That's updating the issue itself, which as noted there, could be quite destructive. Following & unfollowing would be a lot safer to provide a UI for.

Okay, done.

@drumm #6 is a very good point. Here is an issue for it #2416513: Provide a UI for mass unfollowing and following of issues