Noob Question On Buildbot and the signing key process

So I am poking around the LCNC documentation and reading about the installation processes etc. The following information in the buildbot section has me wondering something. Please bear with me as I am a very casual Linux user so this may come off as a stupid question.
First, here’s the info that I am referring to -
---
To use these packages on your computer, first add the buildbot archive signing key to your apt keychain by running this command in a terminal:
sudo apt-key adv --keyserver hkp://keys.openpgp.org --recv-key EF1B07FEE0EE663E
(Key fingerprint = 4FA2 D1ED 5B2F 38AB 01A4 AB7E EF1B 07FE E0EE 663E)

Also can be used -
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv-key 3cb9fd148f374fef
---

Here’s my question – are these hexadecimal strings that are in these commands “cast in stone”? I mean can they change over time and perhaps ones that are quoted in older posts / threads are no longer valid? Not that I have seen any that are different than this, I’m just wondering. Again, bear with me, I am a casual Linux user and don’t understand a tap of this – lol. Maybe someone can also explain what is going on with this command and why it’s used in general.

Thanks very much for your patience !

Usually it stays the same, i have noticed it changed once probably when 2.8 got out.
It is a security feature to make sure the server hosting the packages is the legal/correct one, not some shady server posing as the original.
Since 2.9 there is no need for it anymore as it is on Debian repositories, so on Debian 12.n all you need is
sudo apt install linuxcnc-uspace
That will install everything, including the real time kernel.

Ok - thanks for the info. I am piddling around with a Rpi3 and found some old instructions to load 2.8 on it along with the RT patch. I'd like to eventually use this Pi3 with a remora based system so perhaps the sluggishness of the Pi3 won't matter much if the stepper control is all being done off-Pi anyway. It's early days yet for me - much reading and learning to go yet.
Cheers

Can you also install the dev version as well with this method on Debian12.n ?
ie - sudo apt-get install linuxcnc-uspace linuxcnc-uspace-dev

Yes, but it should be already installed, test by running in a terminal
halcompile --help

tommylight wrote:

Since 2.9 there is no need for it anymore as it is on Debian repositories, so on Debian 12.n all you need is
sudo apt install linuxcnc-uspace
That will install everything, including the real time kernel.

This will install a very old version of linuxcnc of linuxcnc 2.9. A better solution is to go to the docs and read heading 7.1 of the getting Linuxcnc document and run the script there.  linuxcnc.org/docs/stable/html/getting-st...th_preempt_rt_kernel

The Pi 3 is not supported in Linuxcnc 2.9.2 but that script may work...