A more thorough explanation:

A supplemental declaration is a legal document that is filed after the U.S. Patent and Trademark Office has allowed a patent to be issued. It is a sworn statement that provides additional information about the invention or the patent application.

For example, if a patent application was filed without all the necessary information, a supplemental declaration can be filed to provide the missing information. This can help to strengthen the patent and make it more likely to be granted.

Another example of when a supplemental declaration may be filed is if new information becomes available after the patent application has been filed. This new information can be submitted in a supplemental declaration to help support the patent application.

Overall, a supplemental declaration is an important legal document that can help to strengthen a patent application and increase the chances of the patent being granted.