[Mediawiki-l] Editing special pages / Upload additional file types

[zach bass]

Hi, I'm somewhat of a n00b to MediaWiki administration and have a couple
questions.  Apologies if these have been answered before, but I checked
the list archives and web and haven't been able to find clear answers.

1.  Is it possible to edit special pages?  It looks like the text for
special pages is stored in the database and is non-editable binary data,
and that these database fields are populated from the file
./languages/Language.php, but changing the text in this file has no
effect--is this data just imported to the database when the Wiki is first
set up?  Is there any way to pull in new changes from this file?

2.  Is it possible to allow uploads of all file types (versus only images,
audio, or video)?  I'd like to permit users to upload PDFs, .xls, .doc,
etc so they can store templates, documentation, etc.

3.  Is there a way to add your own special pages that contain PHP code? 
I'd like to embed a PHP tool into a new Wiki page (this page doesn't have
to be editable by users).  I'm pretty sure this is possible, but not sure
what's the best/recommended way.

Thanks!
-zach