Final answer:
The plugin required for translating the content of a catalog item is the Multilingual Catalog plugin [com.glide.multilingual_catalog]. This plugin enables the management of multi-language catalog items.
Step-by-step explanation:
To allow translating the content of a catalog item to a supported language on a platform like ServiceNow, the correct plugin that needs to be activated is the Multilingual Catalog plugin [com.glide.multilingual_catalog]. This plugin will enable the creation and management of catalog items in multiple languages, facilitating a multilingual user experience.