Agreed. I love kvaesitso and I use it. But these conversions is something I simply dont use, because entering the units the way it expects is too cumbersome for me most of the time.

Same thing for timers. I hate having to type “15 min” instead of “15min” which feels much more natural to me.

Nope. It is an android app. The author is probably using some kind of webview to display the data, so html and css are for laying out and styling the components. This is pretty common nowadays