The Chinese wikipedia page for vertical bars only talks about:
In the book《成都方言》I'm seeing this type of xiehouyu with a vertical bar in the middle of the "注":
My best guess is that it meant either/or but then under the entry for 钵 it's written the same way:
钵 bo 钵钵，钵儿，陶盆：鸡吃一撮，狗吃一～。歇后语：“缸～头的泥鳅儿——耍团转│滑不了。”
No indications of different usage that I can see here.
What does the vertical bar do here? What does it mean? Is it either/or?