Ever double-click on your TechTree.xml, only to get a rather difficult to read display in Internet Explorer? Here's a handy way to make it more legible:

Open TechTree.xml, and insert this as the second line:
< ?xml-stylesheet type="text/css" href="techtree.css"? >
(Remove space between "< ?" and "? >")

Then save this TechTree.css file to the same folder that TechTree.xml is in. (does not over-write any files)

Now if you double click your techtree.xml, it will be much easier to read