The Trello Card ID Add-on for Firefox is a utility designed for developers and users of Trello who need quick access to card IDs for various tasks, such as code commits or references. This add-on simplifies the process of obtaining card IDs by allowing users to easily copy them to the clipboard with a single click, enhancing workflow efficiency. It is particularly useful in scenarios where the full card title may be cumbersome or unnecessary.

However, it is important to note some limitations of the add-on. Newly created Trello cards may not display an ID initially due to a missing HTML element; users can resolve this by refreshing the page. Additionally, the formatting of card IDs may vary based on language settings, with the add-on primarily aiming to present IDs in a standard format (e.g., "#3"). Despite these issues, the Trello Card ID Add-on remains a practical tool for Trello users.