Discord History Tracker. Very interestingly shaped piece of software. You install and run a localhost web application on your own machine, then paste some JavaScript into the Discord Electron app’s DevTools console (ignoring the prominent messages there warning you not to paste anything into it). The JavaScript scrapes messages you can see in Discord and submits them back to that localhost application, which writes them to a SQLite database for you. It’s written in C# with ASP.NET Core, but complied executables are provided for Windows, macOS and Linux. I had to allow execution of four different unsigned binaries to get this working on my Mac.