That sounds really interesting, although too limited for my current work focus which deals with Really Big logs.

I tried the demo link, it rendered a lonely @ at the top left of the page, the rest was blank. The console said:

    Uncaught TypeError: [].filter(...).reverse()[0] is undefined
        onload https://ljw1004.github.io/seaoflogs/demo.html:14

This was in Firefox 98.0 in Windows.