I have written to the almighty Otto. Exactly 20 minutes later the reply came in:
From what I can tell, you discovered that profiles doesn’t like spaces
in names (we know), and so you made a username without a space in the
name. Now you want to transfer a plugin from the old spaced account to
the new spaceless one.
This is easy. You can do it yourself.
Step 1: Add the new account name as a committer. You appear to have done that.
Step 2: Change the readme.txt file that comes with the plugin to have
your new account name on the Contributors line.
Step 3: Wait for the plugin data to update itself.
We don’t really change account names or “transfer” things between them.
I did it so. Then I have removed the whitespaced profile from the commiter list. Now everything is nice. This is the last post from my old account.