“The new alliance includes the YPG, various Arab groups including Jaysh al-Thuwwar (Army of Rebels) and the Arab tribal Jaysh al-Sanadeed, and an Assyrian Christian group, according to a statement announcing its establishment.”
This is from Reuters. Their veracity is already in question, and claims that the Kurds and any element of the Islamic resistance to Bashar al-Assad have formed a meaningful alliance are not really credible.
The Kurds really fared much better under the secular rule of Assad, as he was not into the religious persecution thing that EVERY Islamic Jihadist conducts against minorities.