Apologies if this is in the docs, but I haven't been able to find it. When configuring a plugin with an environment variable, how do we know when to use one or two underscores between the plugin name and the configuration setting? Example: •

TAP_POSTGRES__SELECT

•

TAP_POSTGRES_DATABASE

Is it related to whether it's a setting common to all plugins vs when it's a plugin-specific setting?

https://docs.meltano.com/concepts/plugins/#extras https://docs.meltano.com/guide/configuration#plugin-extras Those with two underscores are 'extras' - a set of reserved options for use with extractors (and other plugins) that are used by Meltano, more information at the links.