Google launched AdSense Labs to give publishers access to test newer features.
You can find it under the Optimization tab. If you are eligible, you will find new experimental features.
Google will start the lab with two new labs, Show fewer ads and Inline ads. If you don’t see these options in your AdSense dashboard, it means, Google does not think it is suitable for your site.
Show fewer ads
This option will reduce the number of ads on your website. But, the impact on revenue is negligible. It will remove at least 10% of the ads served on your site (1% or less of your revenue). It will prevent users to see low-value ads. You can learn more about it here.
These are Inline ads with 320×100 size. That are automatically inserted within your mobile site as a user scrolls down the page. Now you don’t have to write a code to dynamically insert ad units on your page. Google will do it for you. For more information on Inline ads, check out the Help Center.
Google will add new Labs over time for you. So you can check them in upcoming weeks.