Hi,
I can answer that and in fact it’s on the top of the introduction concerning MR API:
It’s talking about developers, not necessarily musicians. Steinberg with this API never really targeted the latter. The API guide was mostly for devs of MIDI controllers.
At the same time, there are musicians with some knowledge of js, willing to dive into it, hence the “primary purpose” note in the introduction. But this was - and is - the exception.
So a “manual” of any form, was simply out of context. It couldn’t take it from the start, teaching basics of js, it’s just another API for devs.
While being present at this forum, and acknowledging this fact, that musicians cannot really be into scripting by default, but at the same time, seeing some trying to, I’ve always tried to help them out with their scripting attempts. I must say, I’ve been surprised to even see them trying to use/master this unknown/exotic to them environment. It’s like asking from a dev who’s never been into music to use/master Fugue. I guess he/she would ask for a manual too. This is just not feasible.
To the point:
New controllers that I see, get into the MR thing. This was expected.
Older controllers use other implementations (most of the time I see MCU/HUI). These are fine too, and some times even have some advantages over the new ones. Manufacturers weren’t obliged to build MRs for these. We bought it with a specific functionality offered.
And then there are enthusiasts trying to build their own controllers or reshape the functionality of existing ones. In this latter case, one may use the mapping assistant concept of Cubase which was actually the one designed for musicians in the first place, or give the API a try, by getting help here or from friends into js. A short note here: If I were strictly a musician and not a dev, I would focus on pressing Steinberg to deliver even more functionality and/or consistency to this specific area. NOT the API.
Finally there are pros, mixing engineers, who for one reason or another, are not happy with either whichever implementation their controllers host, or the MR assistant. These guys do this for a living, my opinion is that they should hire someone who codes for a living. It’s as simple as that.