If you want to manually remove our app code from the store theme, follow these steps:
1) Visit Store Admin >> Online Store >> Themes >> Actions >> Edit Code
2) Click on the theme.liquid file in the layout section.
3) The theme.liquid file will be opened in the editor.
4) Remove the {% include 'za_product_blocker' %} code that are located below <head> tags in the theme.liquid file
5) Click the Save button to save changes.
6) Now go to the Snippet section and click on the za_product_blocker.liquid file
7)The za_product_blocker.liquid file will be opened in the editor.
8) Click the Delete button to remove the file from the theme.
Now our app code has been removed from your store.