DI??

"DI" in a rig's name usually refers to the fact that this profile was taken from the fx-loop send. It contains only the preamp.
These are used to play through a tube(!) power amp and a guitar cabinet.

they are suited for the small number of people that use a tube power amp into a guitar cabinet.
generally, when somebody wants to use a cabinet, they go for a Profiler with internal power amp and ideally use a merged profile.
this way you get authentic raw amp tone (for your cabinet) and the full studio profile (for the FOH)

Quote from DonPetersen

"DI" in a rig's name usually refers to the fact that this profile was taken from the fx-loop send. It contains only the preamp.
These are used to play through a tube(!) power amp and a guitar cabinet.

While this reflects the terminology that probably SHOULD be used, a lot of profiles labeled as DI is actually "DA" (Direct AMP) profiles - i.e. taken not from the effects loop, but from the speaker output using an attenuator. For these, you'd put a cab from another profile in it, or use it with a power amp (preferably solid state) and a cab.

Quote from Michael_dk

While this reflects the terminology that probably SHOULD be used, a lot of profiles labeled as DI is actually "DA" (Direct AMP) profiles - i.e. taken not from the effects loop, but from the speaker output using an attenuator. For these, you'd put a cab from another profile in it, or use it with a power amp (preferably solid state) and a cab.

Oh wow, that makes a lot more sense. I just thought it was called "DI" profile cause you do that with a DI box (or also attenuator as you wrote).
Direct Amp profile makes a lot more sense and it's also what it is called in the manual. No idea why I went with "DI" myself.
I feel slightly dumb now haha

So...
DI = preamp signal from effects loop / to be used with tube power amp.
DA = signal from speaker load (via direct box) / to be used with solid state power amp (kemper powerhead or other)
Merged = combination of DI or DA with a cab sim / used simultaneously DI or DA with speaker cab and DI or DA with cab sim to FOH
Studio = signal caricatured from the mic'd cabinet / use with FRFR speaker and recording studio tracks

..is this correct?
I'm sure there is more to it, but this is what my mind is thinking...

So...
DI = preamp signal from effects loop / to be used with tube power amp.
DA = signal from speaker load (via direct box) / to be used with solid state power amp (kemper powerhead or other)
In an ideal world, yes. But profilers have not been entirely true to this definition all the time - so often "DI" will actually mean "DA".

Merged = combination of DI or DA with a cab sim / used simultaneously DI or DA with speaker cab and DI or DA with cab sim to FOH
Merged would only make sense as a cab merged with a DA profile (although a DA profile might erroneously be named "DI", as stated above).
Merged is a process where two profiles are taken; one with the usual mics etc, and another with a "DI box" able to handle the signal directly from the speaker output of the amp (this box is why profiles are sometimes labeled DI when they ideally should have been labeled DA). This second profile thus has no cab.
You only get a MERGED profile when those ttwo profiles are MERGED in the kemper. It means that the kemper knows exactly which part of the profile is the cab, and which is the amp, instead of having to estimate this.
Merged profiles behave exactly like "regular" profiles (called "studio" profiles), except the amp portion being more authentic when turning the cab of the kemper off. This then gives you a more authentic result when hooking up an external guitar cab (i.e. a real one).
With an frfr speaker, you'd still leave the cab turned on inside the profile.

"More authentic" doesn't NECESSARILY mean "better", of course.

Studio = signal caricatured from the mic'd cabinet / use with FRFR speaker and recording studio tracks

..is this correct?
I'm sure there is more to it, but this is what my mind is thinking...

Look in the manual for precise explanations.