Leiche - That's just it - nothing I can find either converts or plays it, other than as a stream from Internet. If, say, VLC, could play it - it might be able to re-record it as something else - preferably Flac or WAV, lossless.
Gnome Recorder 2.32.0, as in PCLOS Repos, is an excellent and very well-behaved device, and when the AAC+ on a site is run via browser, it will record the stream AND convert it to Flac, WAV, Ogg, MP3, etc. Also what it calls "AAC - M4A type". WAV and Ogg work very well - but Audacity and SoundKonverter won't touch the version of Flac it converts the AAC+ to.
If the "AAC - M4A type" is selected and downloaded - as with other AAC+ files I have - nothing I can find will play or convert it.
However - if the source recorded from is "Std AAC" - and the record-mode is "AAC - M4A type" - that plays or converts in the devices that usually handle standard AAC - example - AAC audio stripped out of a video from that tubular-type place.
Apparently one of the reasons our Oz Great Leaders (?) - chose DAB+, not the usual-overseas standard DAB - is that it transmits in 64kbps AAC+ - and should the "disobedient peasants" dare record it - they'll find it very difficult to do anything with. I don't have a DAB+ radio - but have had a few files recorded from one - and no - I can't do anything with them - either!
From Googling-around - it seems that at and above 64kbps, standard AAC is good audio, below that it isn't. So folk invented High Efficiency AAC - HE-AAC - also called AAC+ - which is quite reasonable broadcast / streaming quality at 48-64kbps. Allegedly equal at 64kbps to MP3 at 128kbps, though folk on audio forums say, actually similar to MP3 at 96kbps. And notably inferior to FM, either for broadcast listening or recording.
Just18 - I haven't tried the Perl converter for AAC+ - thanks for the heads-up on that - shall get it, soonest! As for samples - I run the online AAC+ station with Firefox - and use Gnome Recorder in one of its modes to record. This system is running PulseAudio - I don't know if Recorder does that - or "all the formats" without. However, I can record the AAC+ with Recorder's "AAC - M4A type" mode - and obtain files that none of my present apps or tools will touch... Shall see if the Perl device does - and blessings be upon you, if it does...!