Browser app marketplaces

Browser, distinct from the browser-extension-store tag, marks the browsers in this directory — Opera and Safari — whose extension ecosystems let a developer change the browsing experience itself for end users, rather than integrating with a separate business platform.

Both accept the same WebExtensions API used by Chrome and Firefox with only minor manifest differences, so an extension built once can reasonably target all four with incremental porting effort rather than a rewrite.