The files a render produces

Each render saves two files that share the output name: the audio seed (.mp3 or .wav) and a MIDI file (.mid) of the same progression. The result panel lists both, and clicking either one reveals it in your file manager. They land in the folder of the seed's .yams, right beside it.

They're for two different jobs. The audio is the seed you actually upload to the AI generator — it's the whole point of the app. The MIDI is a bonus for music software: open it in a DAW and you have the same progression as editable notes. If you only ever upload to Suno, the MIDI costs nothing sitting there. The .yams seed file in that same folder is a third thing, but it isn't produced by rendering — it's the document you saved to create the seed, covered next.