Open the Media Library dialog of an entity reference field that uses the media library widget, by the field's machine name. Core renders the open button with the id edit-<field>-open-button (with a random suffix once the form has been rebuilt by AJAX), so the visible button whose id contains that fragment is the one clicked. Re-tries the click once when a previous dialog's close animation tore the new one down.
Examples
When I open the "field_media" media library
And I open the "field_image" media library
When we open the "field_media_image" media library
And I open the "field_hero" media library
When I open the "field_gallery" media library
Pattern
When(/^(I |we )*open the "([^"]*)" media library$/, …)
Part of @webship-js/drupal-core-steps (github.com/webship/drupal-core-steps), a step pack for Webship-js 2.0.x.