447–450: skips empty property names (it splits the string by commas, and if two commas in a row are encountered, it would create an empty property)
451–453: checks if user-specified alias for the property exists (index 1): if so, uses it. Otherwise uses the name of the property itself (index 0). This is what comes before the colon.
455: adds a colon followed by the value of the property in bold (<b>).
What you want to do is to swap the latter two blocks (and perhaps remove the colon, bold tag, etc.)
@ilyankou - currently, the order of items in polygon pop-ups is hard to parse: label, data
would you consider flipping the order to data, label?
@jordanpolitz requests this for her project, so if you don't want to change the code for everyone, perhaps show us where to change it for her version