If you know how to decompile, then you shoudn't be asking such simple questions like where to start searching.
I'm sorry, man. I am trying not to be a downer, but I don't want to take responsability if you break your phone. Figure it out on your own.
EDIT:
Bad news for you,
@HitFan
I don't think it's as easy as I originally thought. I succeded in modifying it to my needs (removing the brightness slider) but I failed to make the text not bold.
The simple modification from bold to normal resulted in the total lack of a theme and status bar/notification drawer.
So you better be very sure what are you messing with and have a backup (plan).
Also, in the 3.29 weekly for my Note 5A the text is bold even on chinese notifications.
It's also curious that after I removed the notification slider the charging sound changed and the toggle became inactive just at this moment. I'm pretty sure that with the untouched Global notification the toggle works fine.
@Soebianto do you know where the charging sounds are supposed to be
going? I spotted a couple of oggs in the decompiled files, and I guess they are being extracted somewhere (and renamed?). My first guess was system/media/audio/ui but that was a fail. Also the charging sound that's playing now is nowhere to be found on my system, which is quite weird. And I don't really beleive in a broken archive or a hidden error during recompilation because everything else is working like before.
I get the text thing, it depends on themes and fonts.
I didn't delete or modify the contents of the brightness slider file, I just
tagged it hidden. How can a couple of words in a file which itself is called in another file to affect totally another part of the app?