Title bar, Toolbar, and Inactive tabs

What the three top image slots in the creator affect.

These map to the first three items in the creator Images panel:

Creator label	What it affects	Technical name
Title bar	Window title bar and tab strip	`theme_frame`
Toolbar	The row with the address bar	`theme_toolbar`
Inactive tabs	Background of inactive tabs	`theme_tab_background`

Check the preview on the right in the creator after changes, or install in Chrome to confirm.