How to remove shower drain
The lettering on the drain cover leads to a number of similar (but not exactly the same) products all over the 'net. What is consistent about this particular company's line of products is that the words "snap-in" appear frequently.



The image above differs from yours in that your "tab" area is much thinner and does not show clearly any tabs. If you are able to shine light into the area of the slots and are able to see tabs, one can expect that it too is a snap-in cover.

Even a rather comprehensive installation document for plumbing a Florestone shower pan includes nothing about the drain cover. This is consistent with one being able to see the removed cover and recognizing that it is a snap-in type. In place, it's not so easy to determine that aspect.

Image courtesy of Decour Glamour web page.