Description copied from closed duplicate ticket:

Issue Summary

Currently, if you deactivate/remove a user from your site, you won't be able to search for their shared dashboards/filters; although you can extract this data using REST API, this can be time-consuming. 

It would be great to search for deactivated users who own shared dashboards/filters through the UI instead of using REST API.

Steps to Reproduce

1. Create a dashboard/filter and share it with your organization.
2. Deactivate/remove the user used to create it.
3. Try to search for the owner; even if the dashboard is available, you can't search for the owner's name. 
   • The same behavior can be observed under Settings > System > Dashboards/Filters.

In the example below, the user "Joe Doe" was deactivated:

Workaround

You can use REST API endpoints to search for shared dashboards and filters deactivated/removed users' own as a workaround.

Dashboards:

• GET: Search for dashboards

Filters:
GET: Search for filters
A user with the Administer Jira Global permission can go to 
YOUR_SITE_NAME.atlassian.net/rest/api/3/filter/search?expand=jql&overrideSharePermissions=true

This will return all filters including private ones.

Original Description

When a user is deleted and the boards are private, it could cause visibility problems because the boards cannot be accessed, the way to fix this is by going through the manage filters page to change the owners, however, it is not possible to narrow the search for former users causing a lot of manual work to search in all the filters.

It would be good to add an option to search for filters where the owner is a former user.