Inspired by this question.
It seems to be a common minhag to have a special trope for the end of a chapter when leining the megillot. I have seen this done in my shul, have done it myself, and also heard on various recordings, e.g. Rav Chaim Fessel for all five, and Rabbi Jeremy Wieder for Esther and Kohelet. (Interestingly, Rabbi Wieder only does this trope at the end of Ruth and Shir haShirim, but not at individual chapter breaks, and he doesn't do it at all for Eicha.)
My understanding is that the origin of the chapter breaks is Christian, and that there's no Jewish source for them, see e.g. Wikipedia. If this is correct, why do those who do an end of chapter trope mark these chapter breaks? If this is incorrect, where are the chapter breaks mentioned in Jewish sources?