Update 12/16/2018
-It appears after further experimentation that these symbols may not be generated from ReSharper… I will continue to pay attention and see if we can figure out exactly what these are doing…

I noticed some strange symbols appearing  in Visual Studio 2017 recently.

They constantly change as type, and seem to have something to do with line breaks or spaces.  They appear to be generated by ReSharper, as they disappeared when I disabled the extension. I have posted to to ReSharper Community here seeking documentation.

 Post on ReSharper Community Site

This area to the left of the line numbers in the left-side bar is called the “Indicator Margin”. Is used for other things such as breakpoints and bookmarks. 

rned is called the “Indicator Margin” in Visual Studio 2017. This is the left-hand side bar that appears