One file, StreamWindows.plugin.js, for BetterDiscord. The button fetches the current version from the download repository on GitHub, the same file the plugin updates itself from.
.plugin.js.github.com/relyTzzz/DiscordPlugin, run npm install, then npm run build:bd writes dist/StreamWindows.plugin.js; npm run install:bd copies it straight into your plugins folder. The source builds a Vencord version from the same code too, described in the guide.There is nothing to do. Each time Discord starts, StreamWindows compares its own version with this file and, when a newer one exists, asks whether to update; agree and it replaces its file, which BetterDiscord reloads at once. To check by hand, open Discord's console (Ctrl+Shift+I) and run $sw.checkForUpdates(). You can also just download the new file and replace the old one.
The plugin is plain, readable JavaScript, not minified. Its first lines are a header with its name, version and where it comes from, and BetterDiscord shows the same on the plugin's card. If you are ever unsure of a copy, download it again from this page.
The guide covers the controls, updating, troubleshooting and the Vencord build.