It is 内幸(うちさいわい) - 篤姫 其ノ二 by 吉俣良. The file name is afternoon_warm.mp3.
Ok check this out https://youtube.com/playlist?list=PLr53FAeuAoA2JIWLyMB8MDXCFzOBEYE-x&si=rqoUTGxh...
You can find the audio files in Repeat\game\audio.
