GIven the etymology and the evidence of most examples, this is a counter-charm against other magical spells. See D. Levene, "'This is a qyblˀ for Overturning Sorceries’: Form, Formula--Threads in a Web of Transmission", in G. Bohak, et al., eds, Continuity and Innovation in the Magical Tradition (Leiden: Brill, 2011) pp. 219ff. However in Jewish Aramaic Curse Texts from Late-Antique Mesopotamia (Brill, 2013) pp. 10ff. Levene goes further and suggests that since many of the qibla bowls are duplicate pairs that were sealed together by bitumen that the connection with the meaning "darkness" may be involved and that "counter" is not necessary.