Turkish tanks enter Syria, page-4

Unlike the Armenians and the Yazidis, the Kurds have a battle hardened army (20,000 front line soldiers and about 40,000 reserve type fighters + another 10,000 allied Arab, Turkman, Yazidi and Assyrian fighters) within Syria that is supported by the United States and a third column of about 20,000 battle hardened HPG fighters within Turkey itself. In addition, around 20% of the Turkish population is Kurdish.

That said, I believe that all sides know the unofficial dotted lines on the map that are unofficially accepted by the US and by Russia and the Syrian Kurds received a briefing by Brett McGurk 2 weeks ago on what may happen next.

cheers