I've spent some time today trying to find where the icons are stored for the search bar, but I couldn't.
There is no longer a
/usr/share/webkit-1.0/pillow/assets/search_bar folder on newer firmwares.
I've even tried to delete/rename
/usr/share/webkit-1.0/pillow/locales folder which contains all the icons/strings for the different languages, but it didn't have any effect.
I'm not sure where they are stored now and why this locale folder even exists if it's not needed. I've tried searching for any other images on the firmware but didn't find the store icon anywhere else.
Edit: Seems like they completely moved this from
search_bar.js, removing the file doesn't change anything. Even after a restart, every button functions correctly.