RPMSG file type - Can this be opened and read in FreeBSd?

[byrnejb]

We have received an email wrapped as an eml file containing an rpmsg (Restricted Permissions Message) file. I used munpack to extract the rpmsg file from the eml file. However, I cannot locate any info on how to open this thing without using some form of Outlook or Azure, neither of which I have on my FreeBSD desktop.

Is there any way to get the contents of this on FreeBSD?