Every person who pushes code for, or aids in support for, a plugin is required to have their OWN individual account. These accounts do not have to be personally identifying (that is, you can name them PluginNameSupport1 if you wanted), however all accounts must be used by a single human for your own protection.
There are four roles a user can have with regards to plugins. All can be managed from the advanced view section of a plugin page: