Created attachment 382608 [details] a html file with a search input whose line-height is being set The line-height computed value for input[type="search"] remains fixed (13px in my testing) irrespective of the CSS value specified. Environment Version 13.0.3 (15608.3.10.1.4) macOS Catalina 10.15.1 Have a test case reduction attached here.
<rdar://problem/56849764>
This is about form control painting.
This is due to "-webkit-appearance" CSS property which makes the control use fixed values for e.g. height. "-webkit-appearance: none" loosens it up so that one can size the control freely through line-height, font-size, height etc.