What are these symbols on the batch entry screen?
No, they are not supposed to be there. I suspect there is something amiss with the css on your site; possibly an interfering theme. This is what the screen looks like on dmaster.demo.civicrm.org:



On the other hand, I don't think they are working properly. I believe the checkboxes are supposed to represent that the row has been entered with valid data... but they appear regardless of what's entered. That sounds like a js bug in core.