I did as the extension says .. but ..
It looks like it doesn't go through the articles and change
the name tags. I would think you would want this changed also.
If my original login was Dtsig and now it is Davesigafoos
then I would think that all signatures of Dtsig would be
changed. This can't just be text as it will link to the user
page (which also shouldn't exist ..
right???)
The history all changed.
Hmmm ..
The sigs are written out as wikitext. They won't change automatically.
You may have to change all of that stuff with a bot.