I worked there for 13 years and worked with a lot of people with the title of Product Manager, or "PM" to be specific. And no, we didn't call them "project managers".
Ah, you got me there. My apologies. You're right. I had forgotten that it was "program" and not "product". (I haven't worked there in a few years and probably mixed it up with product manager titles at a different company.)
To me, it always felt like it was supposed to be an intentional "product" role as opposed to "project", but you're right that it basically was a hybrid where they worked on product but also helped manage the project itself.
It was a hybrid role that every org did differently, and it was confusing to everyone and made it hard to separate product focus from execution focus.
Last year they split the roles into Product Manager and Technical Program Manager (TPM), and PM’s had to elect which role/title/path to choose.
This is at least true for the Experiences and Devices and Cloud and AI orgs.
Source: work there now, have been there 6 years.