Sometimes it is necessary for a third party to access WordPress to fix or investigate something.  They will need admin access to WP production or test database.

That is ok, but sometimes they will need access to the SQL database itself.  But that normally requires phpMyAdmin, requires access to the account itself.  Access to the account allows third party access to everything, not just the WP database.

The plugin, WP-phpMyAdmin, is a wrapper around phpMyAdmin which allows a third party with admin access to a WP instance to access the SQL database.

WP phpMyAdmin is a standard plugin included with WordPress.