The daf opens with the Levites' Shir shel Yom, which are in our siddur today too. Also, the Shechinah, as exiled with the people - with real changes to the Second Temple because of those shifts. The Sanhedrin was exiled too, if course, with the list of locales here. Also, a new mishnah, on another if Rabbi Yochanan ben Zakkai's decrees. Specifically, the court stays in its seat even if its head has gone traveling. The Gemara presents a case that counters this decree, or so it would seem. Plus, the commonality of these decrees by R. Yochanan ben Zakkai.