Actually, if the code is unused on the front page it doesn’t mean that you can simply remove it. There are a lot of different elements and styles for pages that are not used on the front page but used on all other pages. That is why it is not possible simply to remove the CSS that you think is not needed on the home page since it will break other pages.
i understand that. of course i will check all the pages that i am using. the question is if it will keep the changes if i am editing the file and save it in the child theme.