Those are good, but they don't work for what the GP is talking about. I'm seeing games/apps associated with my FB account even though I never logged in to FB with them or gave them any info. I literally just opened the app and that activity was associated with my FB account.
I have no idea how they're doing this, since they didn't even request storage access (or I didn't give it). Can any Android developer here chime in on how an app can figure out my Facebook ID even though I don't even have Facebook installed on my phone and didn't give any sort of credential or access to the app?
Try to opt out of Advertising ID (Settings -> Google -> ads) and see if apps continue to be associated with your facebook account. I suspect Swipe sent both your account ad advertising id during login.
Once you've logged into facebook from the device, they likely created a device fingerprint for your device: https://en.wikipedia.org/wiki/Device_fingerprint . This would allow them to identify you even without a cookie or ad id to correlate against.
Fingerprinting across devices is possible too, using things like behavioral analytics, network traffic, timing, third-party data sources etc.
The third party data sources is the easy one. Log into service A on your computer and service A on your phone. Service A fingerprints both and sells the data to service B. Now service B knows how to correlate your behavior between devices even though you never logged in.
I’m sure you’ve logged in something on both your phone and computer. It doesn’t have to be Facebook.
I have no idea how they're doing this, since they didn't even request storage access (or I didn't give it). Can any Android developer here chime in on how an app can figure out my Facebook ID even though I don't even have Facebook installed on my phone and didn't give any sort of credential or access to the app?