If the deletion is required, it must be possible - then Debian could at least distribute copies with the section removed. (And then ship a cleanroom rephrasing of the relevant information in README.Debian).
I wonder how to handle the case where the author of a modified version wishes to comment on that part, also including it. Having lumps of a work that cannot be reused doesn't feel DFSG-free to me, but I might not be thinking straight just now.
b) a copyleft notice that requires that modified versions [...] and to not use the TEI namespace.Preventing non-TEI forms using the TEI namespace seems fine to me, but I could be wrong.I think you're wrong. One should be allowed to derive a document that described the official TEI elements as well as Microsoft's (hypothetical) namespace-invacing extension.
Actually, I think I just phrased it badly, which is a reason to be thankful that I am not writing the licence! I meant that preventing TEI-incompatible and TEI-unauthorised elements from being in the TEI namespace seems fine to me. Putting our own forms into TEI's namespace would be similar to claiming that they said something they did not.
I think you are correct to insist that derived versions including true descriptions of elements already approved by TEI, in the TEI namespace, should be possible.
-- MJR/slef My Opinion Only and possibly not of any group I know. Please http://remember.to/edit_messages on lists to be sure I read http://mjr.towers.org.uk/ gopher://g.towers.org.uk/ slef@jabber.at Creative copyleft computing services via http://www.ttllp.co.uk/