This article is about changing the theme-name and the theme-designer-name associated with your Blogger template.
If your blog has a theme from Google (and indeed the same thing applied to themes from many third-party theme / template providers too), the code has a documentation section at the top.
This section gives the name of the theme, and perhaps the date it was created and the name & website of the designer.
You can see the header in your theme by editing the theme in the usual way. Near the top of the code, just after <b:skin><