Reply To: Using header cover
If you want to get to know the structure of the BP overload files, could I suggest you try installing https://wordpress.org/plugins/bp-template-overloader/ this maps out all of the overload files, it’s pretty daunting the sheer number of files you can modify, but if you look for that one file you can view it’s contents.
Also the link I mentioned but forgot to include about overloading BP is here. https://codex.buddypress.org/themes/theme-compatibility-1-7/a-quick-look-at-1-7-theme-compatibility/