That's not big enough to include even most native components. My essentials build with only common 3rd party libs (like libx264) compresses to 20MB with LZMA2.
I just looked inside the linux appimage. There's only a 2.4MB libffmpeg.so and it doesn't link against anything else than libc stuff.
You are all on point! Great analysis.
- Yes, it's electron (didn't expect such a huge build for such a small app).
- The bundled ffmpeg is probably a light version that comes from the underlying chrome.
- The app detects if there's a ffmpeg available otherwise it downloads the binaries and uses them instead.