The package manager only includes what is downloadable in HG as Dave stated. I suspect that only gets updated on each HG update.
I noticed I can control just about anything with HG and custom programs. I mostly use X10 but heres my list.
3 Amazon Dots
1 Google Home mini
Sonoff low voltage switch
Sonoff inline module
Several dozen x10 appliance and lamp modules
Several X10 inline modules
Several X10 wall switches
1 zwave appliance module
Several milight bulbs both white and color.
3 wijit appliance modules (don’t use the hub)
Several x10 door window sensors
A dozen x10 security motion sensors
X10 DS7000 console.
X10 Airsight xx70
X10 Airsight xx59
EASYN outdoor PTZ camera
Foscam indoor mpeg camera
Basicaly all my TVs which are non smart (LG, Samgung, Sharp)
My cable box (Cisco)
My Shaw direct satellite box
Window Air-con (Maytag)
Notes: I’ve yet to set every thing up in HG but I’ve been able to control these via Alexa utilizing HA-Bridge as a hub in the past. Since I’ve now created a bridge program for HG I can now use it as a middle man. This allows me to arm/Disarm the x10 security console when I arm HG. I’ve also been able to move my cameras to a preset with HA-Bridge.
Since I’m new to using HG and am in the process of moving every thing to a Pi it may be a while before all is running as once was.