“Yesterday you may have seen this article about the latest update to the Magic Tournament Rules (https://magic.wizards.com/en/articles/archive/news/july-magic-tournament-rules-release-notes-2018-07-09).
To better reflect this update, we're changing some of our suggestions for M19 Limited play at the store level and making a small change to what M19 Limited GP will look like.
At the store level, we recommend leaving all cards except for tokens or ad cards in the booster pack while drafting. This means that basic lands, common nonbasic dual lands, and the Nicol Bolas, the Ravager checklist card will all stay in the pack.
For upcoming Limited GP featuring M19, all packs will have a total of 15 cards. The 15th card will be either a basic land or a nonbasic common dual land at the same frequency that they appear in regular boosters.”