I attempted to follow the instructions here to install INDI server on a Raspberry Pi 4 with Buster but ran into problems. First when executing

wget -O - https://www.astroberry.io/repo/key | sudo apt-key add -

The following was displayed in the terminal:
[sudo] password for steve: --2020-04-18 11:48:29--  https://www.astroberry.io/repo/key
Resolving www.astroberry.io (www.astroberry.io)...
Connecting to www.astroberry.io (www.astroberry.io)||:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 4365 (4.3K)
Saving to: ‘STDOUT’

-                   100%[===================>]   4.26K  --.-KB/s    in 0s      

2020-04-18 11:48:29 (155 MB/s) - written to stdout [4365/4365]

Control did not return to the command prompt. There didn't seem to be an error but the sudo thing seems odd. I wasn't prompted for a my password.

Anyway, I hit ctrl-C and ran the next command. No error messages.

Then I executed
sudo apt update

And I received the following error (among other messages):
The following signatures couldn't be verified because the public key is not available

I assume step 1 didn't work so I made sure I'd entered sudo password before running the wget command and then everything worked fine. It seems that these instructions won't work for users that have sudo password enabled. This likely should be clarified in the instructions.