The Product Development Kit (PDK) is a sibling to the Fuchsia Software Development Kit (SDK). Whereas the SDK‘s primary audience is component developers, the PDK’s primary audience is product owners.
The SDK includes everything a developer needs to write Fuchsia components like applications or drivers. This includes the tools necessary to assemble Fuchsia product images[^1], but also includes code and static libraries that are not useful for product owners (unless those product owners are also component developers).
The PDK is a lighter-weight alternative for those product owners.
[^1]: Well, in theory. Some artifacts, like Assembly Input Bundles (AIBs) and companion images are distributed via separate channels for technical and historical reasons. This is also true with the PDK. But conceptually, these artifacts are part of the SDK/PDK, even if they're not literally distributed in the same archive.
The PDK is a subset of the SDK. Therefore, any policies that apply to inclusion in the SDK also apply to inclusion in the PDK.
SDK atoms should be included in the PDK if PDK customers need them.
As with the SDK, support and compatibility guarantees are only extended to our partners. Do not depend on it without approval from Fuchsia SDK leads.
Eventually, we may well want to enable SDK consumers to obtain parts of the SDK à la carte (for example, only downloading static libraries for certain architectures or API levels). In that world, a separate PDK is potentially less valuable, and we may choose to absorb it back into the SDK.