I noticed that lately when I log into a Sitecore instance in Firefox and view the
showconfig.aspx, it does not appear in XML, rather as a string of randomly jumbled words, paths and IDs.
If I open
showconfig in Firefox private mode I get the same result. In the Firefox browser console I see the following:
XML Parsing Error: not well-formed Location: Line Number 1, Column 129:
However, if I log into Sitecore in Chrome and open
showconfig there, it shows the same jumbled mess for a split second, then it shows the XML structure just fine, and no XML related console errors (one favicon.ico 404 is all).
I've tested this with a clean 8.2 rev 170728 instance and a "clean"/unaltered instance of Habitat (same Sitecore version). I am using the latest version of Firefox (61.0.1 right now) and the latest version of Chrome.