...going from memory, it is a list of entries for the first page of the civilopedia/concepts.
I was missing the WFB concepts of morale firesupport and magic in this list.
<Description>TXT_KEY_CONCEPT_MAGIC</Description>
is the list of key entries with description names, works as plain text too, but then you'd lose multiple language support.
<Civilopedia>TXT_KEY_CONCEPT_MAGIC_PEDIA</Civilopedia>
Is indeed the keyentry for the concept of magic in the pedia.
Probably the file is named conceptInfo.
(i'll post name-file and folder later, tonight when I'm home.)
Edit: Tonight, I promise.
Last night I did some text entries, amongst othe things TXT_KEY_YOU_UNIT_FLEE and its enemy counterpart.
I figured I could bundle them into a single xml with my name, just to make things easier to share with you guys.
But it doesn't work. The game complains about it not having a 'sibling' something.

Where does the - 'unit fled' text - belong then?
About integrating the magic tree with the mundane tech tree.
What degree of freedom do we have to change the entire tree?
eg do we desire to stay as close to CIV as possible or will we ransack it totally?