There are 2019sep03 updates:

(1) Developer Study Guide: Deploying BlueZ v5.50 on Raspberry Pi Board

(2) Bluetooth Mesh Models Technical Overview

Question

What is the status of BlueZ, and where is the man page?

Answer

Yes, I could not find good documentation on BlueZ V5.50 installation.

My disappointing progress report on installing BlueZ V5.50.

I have just found a very detailed guide on how to install BlueZ V5.50 on Rpi's including Rpi4B. I hope to try it soon and then report my progress.

References

(1) Developer Study Guide: Deploying BlueZ v5.50 on Raspberry Pi Board (Including Rpi4B)

(2) Bluetooth Mesh Models Technical Overview