Zen Browser

About

Zen is a Firefox fork that rearranges the browser around a sidebar: tabs stack vertically, workspaces keep projects apart, a compact mode hides the chrome until you need it, so pages get the whole window. Tabs can be split side by side, pinned, renamed and filed into folders, the address bar doubles as a launcher, and the look is themed from settings instead of a separate theme file. Because it is Firefox underneath, it uses the same WebExtensions, so most Firefox add-ons and privacy extensions work as they are, and no account or telemetry is required. Zen Mods restyle the interface further, and the project is free and open source under MPL-2.0 with macOS 10.15 or later supported.