Some questions around Bluetooth Server

Thanks for the feedback, it gave me something to think about. I'm still, and will be for next time, in the steep part of learning curve. Please see my comments.

• oh, writable is indeed an americanism, have been in the States for more than 20 times, and never heard this. Never stop learning.....
  
• looks like nRF does not support an read-event :-(
  
• take a look to https://www.bluetooth.com/specifications/assigned-numbers/format-types and https://www.bluetooth.com/specifications/assigned-numbers/units. I've no idea, how important/helpful this is, or could be. Found it by working through some sources for ESP32.
  
• I tried this {0xBBCC : { 0x1358 : { value : "Hello", readable : true, description:"bbcc 1358" } } } and took a closer look with nRF Connect. There is a list of descriptors with 1 entry. read this description and you will get the description "bbcc 1358". According to the arrows in nRF connect, both read and write are supported for this descriptor. I would prefer to support read only.
  
• For ESP32 value is stored, let me say, somewhere. Right now I use hiddenRoot for this. In READ-Event I read the value and copy/send it in a response. Therefore, it is easy to write functions to read and write the value in hiddenRoot. As far as I understand, for nRF everything is stored inside only.