I am trying to use Flask and for some reason it is rendering with a byte-order mark that's a quirk of something using UTF8 (the mark is in particular for people googling the same issue).
I do not know how to get rid of it or if it is a source of some of my problems. I am using Flask on Windows 10.
I wish I knew how to reproduce this issue.
The string (BOM) is most likely included in your template file. Open/save it in some editor which doesn't include unnecessary symbols in UTF-8 files. For example Notepad++.