Hi! As the header said: I’m trying to delete a footer but I don’t know how to do is. All I can find is a function to replace it by a new footer. Isn’t it possible to submit a theme without footer?
Thanks!
Is it for Firefox? Which version?
The new Lightweight Themes don’t have a footer.
https://developer.mozilla.org/en-US/Add-ons/Themes/Lightweight_themes
It’s firefox 56.0
I clicked on your link and on “submit it right now” and I get re-directed to the same page that I used for uploading my theme. There are two options to upload images: One for a header, one for a footer.
TBH, I am not an expert on Themes but it seems the submission page (https://addons.mozilla.org/en-US/developers/theme/submit) needs to be updated. 
I will refer this to @jorgev
Theme footers should now be optional. We will remove that input in future iterations of the theme upload tool, but at the moment it’s just a minor inconvenience in the form. Deleting it is unnecessary, since it’s unused.