Do you know of an example of a commonly used application which uses the emacs-driven functionality you're referencing, but where the application isn't generally

Do you know of an example of a commonly used application which uses the emacs-driven functionality you're referencing, but where the application isn't generally used inside of emacs itself? I.e. do you know of a widely-used program which uses emacs as a library, but not as the top-level application? This is a slightly leading question -- I certainly don't use any such applications, and am not really familiar with any, though I can't say I've ever looked. But I think the above, as other commenters have mentioned, has a lot to do with why this isn't really a good comparison. Even more so given that even if such applications do exist, programmers definitely like using libraries written or wrapped in their host language over ones simply available over FFI, so someone'd still want the functionality from elisp wrapped in a native API (a Python one in this case).