I missed the note on there but apparently ;
Change log
- [New Feature] support ExpertRaw mode
That said, I believe those of us with 15.0.01.71 are signed with 29c6, the APK is signed 9ca5. Not compatible for us and fails install.
The other two posters on the innuendo build number probably are 9ca5 signed and could give it a try.
Edit: Above may not be accurate. I haven't had time between work, not sleeping and zoning out to check the signature. All the randomly clicked builds I checked on apkmirror use 9ca5. It's possible, though unlikely (I don't give Samsung that much credit), that Samsung embedded network date based block in the last firmware after which it will be released officially in the store and be installable side loaded. I doubt another firmware update will come out to unlock it with how things have been going but could be wrong.
This all might be a publicity hype to get outlets like OP mentioned to report on "hey it there's something new out there"