From the README:

This is a fork of the original Adium (source) that revives and modernizes it for current macOS. It began as an Apple Silicon (arm64) port, as the original is an Intel-only binary from 2021. Since then much has changed: WhatsApp, Telegram, Signal and Microsoft Teams arrived next to the classic services that stood the test of time, encrypted voice and video calls over XMPP, full Dark Mode, replies straight from Notification Center banners, a rebuilt System Settings-style preferences window, a WKWebView message view, and a long list of fixes for how modern macOS behaves.