How to listen to iMac G3 audio files with no extension on a recent device?
https://recording.org/threads/optimizing-imac-for-audio-recording.10348/ Is it Digital Performer ? Also, make a backup of all audio files and perform experiments on a new copy.


  Raw files can have a wide range of file extensions, common ones being .raw, .pcm, or .sam. They can also have no extension.


https://en.wikipedia.org/wiki/Raw_audio_format

So you can rename one of the files to add the extensions like 



  .raw files can really contain anything, the extension really provides no clue.


  .sam files are by far the most common raw file one can encounter, these are 8-bit signed PCM. They were employed extensively along with EA IFF 8SVX files as samples in Amiga tracker software.


  .pcm files might provide a clue that the file contains linear PCM, as opposed to encodings such as the various types of delta and companding encodings and compressed streams, this could still be any bit depth and ordering.



https://web.archive.org/web/20160525083851/http://www.fmtz.com/misc/raw-audio-file-formats

Other than that, use some audio software like Audacity which  supports importing raw formats.


  The two most common uncompressed file types you will encounter are WAV and AIFF.


https://manual.audacityteam.org/man/importing_audio.html