Developer iBSparkes announced the feat in a post Twitter.
ya'll talk that life me and @qwertyoruiopz really live it
Attached to the post was an image of an iPhone 8 running Cydia on iOS 13.0.
Currently, the unc0ver and chimera jailbreaks only support up to iOS 12.1.2. It's unclear if iBSparkes or qwertyoruiopz have any intention of releasing their jailbreak if the exploits used still work in the final version of iOS 13.
Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.