The current output function Auto Level can do that (as mentioned in the manual). Max Gain 0, Headroom 6, Rise Time 1. Limits the RMS output level to around -10 dBFS.

I've found the manual explanation of Auto Level to be sparse, at best, so this sort of helps. Any more elaboration could be quite helpful, thanks.

No. I just tried it with music and watched the level meter.

Indeed I was astonished now to not find in the manual what I thought is in there. I remember that I had explained how it works and why it can be used as 'long-term leveler' as well as 'output protector' or 'max volume limiter'. I will search tomorrow where that information hides.

Proposal for description text:

While the Compressor is mainly used to reduce signal levels above a certain threshold, Auto Level is a combination of limiter and signal amplifier, affecting levels around a certain threshold. The headroom setting sets the threshold from -3 dBFS down to -12 dBFS, which then also reduces the output level accordingly. The amount of amplification and the 'rise time' are also adjustable. The 'attack time' for lowering amplification when high level signals occur is a few ms.  Auto Level works pre-fader, so any loss in volume can be compensated by rasing the fader above 0 dB.

With only three simple controls Auto Level can be used as maximum volume limiter at the hardware outputs (factory preset Output Protector), to add some digital style, fast compression with and without the Compressor, or to operate more traditionally as fast or slow averaging leveler (again check the included factory presets). Note that Auto Level both reduces and increases gain. The channel's level meter in combination with the gain reduction meter gives an easy to understand display of how the function changes the signal.

If that is ok then my main problem is to find the space for it in the manual