Now that asynchronous programming is supported in JavaScript through Promises, it is easy to display either timed or persisting notices in a non-modal way, so that the notices can be dragged to another place on the screen or all notices can be dismissed or even temporarily dismissed by a click anywhere in the notice box or even on the game board background or by pressing Esc. Such programming these days is basically simple.
Not that I’m going to learn how OGS is programmed and built, no way. I make my own projects modular and easy to build, but that is not the way most software developers work. (I’m retired from a 40 year career in software engineering in companies large and small.)