I think it might be, there’s no way Anakin would be able to buy proprietary hardware or software. So either he stole it, which his mother probably would not have allowed. Or he was able to scrap all the parts together because there is a template for humanoid protocol droids that we have also seen round Star Wars. And then the software itself either Anakin programed entirely himself, (which I know he’s very smart, but even that seems a stretch) or he forked it. So it would make more sense that there was an open source catalog of protocol droid software. It also would make more sense due to the fact that a lot of people have droids, but they are not all created equal. I would think many of the droids on Coruscant were proprietary, while many of the droids in the outer rim are open source.
The internet doesn’t exist in SW, so likely things are based on physical modules; so he probably scavenged, repaired, or assembled a physical module that embodies the droid’s mind and everything is more or less hard-coded. And because the internet–and perhaps copyright law–doesn’t exist, he doesn’t need to activate the module with a central server.
I don’t really even think programming is touched on, it’s more just based on electronics. Software isn’t really at thing.
[Edit: I mean, obviously software exists, but it doesn’t function like real software does in the world. Tech is largely based on droids, which are delightfully physical and embodied for a visual medium, and droids are more like artisanly-modified cars than software that can be updated and copied. That is to say, the technology in Star Wars takes a lot more cues from mechanics and electronics than it does from software and programming. It is a markedy and consciously retro type of future (or should I say “past?”).]
They do have the Holonet which seems to be a sort of amalgamation of media including information that can be looked up.
There’s also the coruscant library that can be accessed anywhere by most people for a fee. Most planets also have their own.