This application reads in a PGN file of chess games, generates a tree of moves from all the games in it, and allows you to browse it using a web interface. The games are observed from the point of view of a given player (let's say you), so you can see how you fare in a certain position as both black and white.
For example, assume the opening 1.e4 d5. The application starts from the initial position, and you would then click on those moves to advance the positions. The application will then show you how many times you have been in this position as both black and white player, and how those games have ended for you (win/draw/loss).
I created this application in order to study my openings, i.e. whether I fall into the same traps over and over again, or if I play some opening badly as white whereas other players would always play it better if I was playing as black.
This application uses Java 16 and the Javalin and Chesslib libraries. On Chrome, the Web Speech API is supported, so you can just click on the page and utter the move you'd like to make (such as "queen takes c5" for "Qxc5"), and the speech recognition thingie will hopefully understand you and advance the situation.