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 I mean can they change over time and perhaps ones that are quoted in older posts / threads are no longer valid?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 !

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

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...