Magento

Go to https://developer.magento.com/extensions/ and log in using benmax login in LastPass.

Click on the Marketplace tab:

NOTE: This is sometimes buggy and redirects you to the actual Marketplace. If this happens, click back in your web browser and try again.

You should land here:

Click on Developer Portal and login again.

You should get here:

From here you can edit and create extensions.