A series of halakhot of what is permitted and not permitted on yom tov. Beginning with some details of shechitah - with concern that it should not appear to be done in the same way as during the week. Also, handling of an urn. And a baker's oven. How much apparent labor did they do back in the day on yom tov itself?! Also, when produce has been set aside, making it muktzah, but it's a shemitah year, and there's no tithing, then one can plan to use from that produce on yom tov. Plus, children who hide figs in a field on Erev Shabbat, and then forgot where they were, and forgot to take terumot and maaserot (not a shemitah year!), the figs are not available until after Shabbat when the tithing has taken place. And one who dries fig in the courtyard, the obligation for terumot and maaserot doesn't kick in until the figs are brought from the courtyard into the house. Which sets the stage for an interchange between Rava and Rav Nachman on these details, and the application of logic vs. mesorah, tradition.