What does "active" mean in SFSafariPageProperties

When my extension loops through all open pages and the page properties, all pages isActive prop returns true.

For example:
  • 2 Safari windows open

  • Window 1 has 2 tabs open (apple.com, bing.com)

  • Window 2 has 3 tabs open (google.com, github.com, extension's bundled html)

  • I am in Window 2 and on my extension' bundled html page

When I run a function that iterates through the pages and returns the isActive prop - all pages return true, except my bundled html page.

(I understand my extension's bundled html page won't return page props, this is not my issue)

What exactly does isActive indicate?

code (perhaps there is a more terse way to write this):
Code Block swift
SFSafariApplication.getAllWindows { (windows) in
        for window in windows {
            window.getAllTabs{ (tabs) in
                for tab in tabs {
                    tab.getPagesWithCompletionHandler { (pages) in
                        if pages != nil {
                            for page in pages! {
                                page.getPropertiesWithCompletionHandler({ props in
                                    let isActive = props?.isActive ?? false
                                    if !isActive {
                                        page.getContainingTab(completionHandler: { tab in
                                            tab.close()
                                        })
                                    }
                                })
                            }
                        }
                    }
                }
            }
        }
    }