When a project is archived, all the saved JQL filters that refer to the project are no longer valid.

Before a project is archived, it would be good to warn the Jira administrator about the possible problems. For example:

"Project X is used in 43 saved filters. Archiving the project will make those filters invalid."

Even more useful would be a list of the filters and their owners, grouped by owner. Then an admin can notify users that are affected by the upcoming change

User                Filter Name

John Smith      My Special Filter (a link to the filter)

John Smith      My Special Filter 2 (a link to the filter)

Bob Smith      Another Filter (a link to the filter)