first of all be aware about your personal data (name, birth, date, ..),
potentially being stored in the file. a string search could be an indicator.
it should be indeed 8bit raw data which you can open and read with a hex-editor,
so you would be able to extract single sensor-measurements, if you know which is which.
if you are willing to help open source developers supporting your file-format,
you could provide a sample after editing out your personal data.
reverse-engineering a file-format should be regarded as fair use and thus legal, but check before.
be also aware that such data could act as a fingerprint for people who own both,
your personal data and the recording.
by doing a websearch, i've found
domino light on their website.
not having windows, i don't know if it has a demo mode and how restricted it is.
could someone maybe try it and write about the experience ?
don't forget to be sure it doesn't call home, nowadays ;-)
alternatively you could send your data in to somnomedics directly
and ask them for your data. they have a web-form specially for that purpose
where you could also attach the file, tough i can't find it yet. somebody else ?