Yellow hover accidently invoked.

Mac Big Sur 11.7.10. I have a yellow text hover both on tooltip and when I hover over text in mail and Open Office (probably other apps as well). I accidentally turned it on using the cmd and shift keys and another key. Ihave been through all the accessibility options but no luck. I don't mind it on the cursor but not wanted when I hover text in mail and editors. How do I turn this off? Thanks.